RS5 carbon clean DIY

Going to post both DIY videos at the beginning making them easier to find.

Starting this thread to hopefully have a central location for a carbon clean DIY for the RS5. Once I get everything together and accomplish the task (with photos/video), we can move it over to the DIY section or I can clean up this thread and repost there. Right now it’s just informational to see if I’m not thinking of something or leaving something out.

I’m trying to gather all the necessary information and parts to accomplish this task in my garage. The local Indy shop does it for $800 which isn’t bad by any means (he also does a full S-tronic and rear diff change for $400!) but it looks as though it’ll run me less than $250 in parts to accomplish this. And quite frankly, I enjoy working on the car.

Looking at the RS5 engine bay, it’s pretty intimidating from a space/service standpoint. Luckily, the A5 line has a service position as Audi calls it, where the entire radiator and bumper assembly can get pulled forward to give you access to the front of the engine. You’ll need this to access the crank and be able to rotate the intake valves for each cylinder to the closed position. I also plan to take the time to inspect all the coolant lines on the front of the engine as there have been a few reports of leaks on RS5’s, especially in hot climates (I’m in one).
Here’s a video that has footage of an S4 front being moved into the service position. Intimidating!


You’ll obviously need a range of tools from a torque wrench to sockets to specialty bits like torx, triple square, etc…

Thanks to a member on another Audi board, there’s an adapter that allows the clean use of walnut shells, creating a loop between the media blaster, the intake port and a shop vac. This reduces the mess to almost zero if you don’t have any mishaps. This is far easier and faster than doing the brush/pick method. JHM also sells an inexpensive kit that utilizes your drill which may speed things up over the “by hand” method. Big thanks to Ford Perfect for whipping this adapter up! Thread here:

Here’s a photo of the port adapter:

The large hole is for the shop vac and the small is for the media blaster nozzle.

I do not own an air compressor so I’ll be hitting up Harbor Freight for one as well as for the media blaster and walnut shells.

Harbor Freight Media Blaster-

Walnut shells, coarse grit (do not get the fine grit)-
Some people have had issues getting the coarse grit to work so I’d suggest finding medium grit on Amazon or elsewhere. The fine grit works but it takes forever and a day according to those who have used it.

Edit: I found medium grit at Home Depot:

Service Position locator pins: Audi P/N T10093 ECS tuning has them,
Alternately, you can use m10 x 150mm bolts from your local hardware store. The thread pitch is 1.5. A 1.25 thread pitch bolt will not work. Also, you can get away with a 100mm bolt, even a 90mm easily.

Crankshaft turning socket: Audi P/N T40058 You can get these less expensively, by a good amount, off of Amazon or eBay. I picked mine up for $20 shipped from eBay. This is pretty much the same one;

Lower intake manifold to cylinder head intake port gaskets, P/N 079 129 717 B (you’ll need eight).

The FSM also mentions the upper manifold gaskets, p/n 07L129717E but does not specifically say they need to be replaced. ECS sells them for $17 EACH. If you’re higher mileage, you may want to consider replacing these.

Flare wrench set. You’ll need a 14mm, 17mm, 18mm and 19mm. But honestly, you can just use regular wrenches.

Include the cost of a full fuel injector rebuild set. The teflon cylinder seals at the end MUST be replaced if you remove the injector and they WILL come up with the lower intake manifold. If you’re high mileage, might be a good time to refresh the injectors/seals since you have everything open anyway.

You CAN get away without using all of the specialty tools as they’re quite expensive. I just happened to have a few pieces which made the work-around very easy. Everything listed below is to get the teflon seal expanded to fit around the end of the nozzle, then shrink it back down to fit snugly in the gap in the injector nozzle shaft. I had a brake bleed kit which had several small cone adapters which were smooth (not stepped) and were also the right diameter. To shrink them, take a zip tie and reverse zip it (smooth side on the inside of the loop) and use pliers to work around the seal and shrink it back down. It works just fine but do take your time.

Injector seal tools, all Audi part numbers (you can probably substitute for the first three:
:diamonds: Puller - T10133/2A-
:diamonds: Hammer - T10133/3-
:diamonds: Nylon Brush - T10133/4-
:diamonds: Assembly Cone - T10133/5-
:diamonds: Guide Sleeve - T10133/6-
:diamonds: Calibration Sleeve - T10133/7-
:diamonds: Calibration Sleeve - T10133/8-
:diamonds: Injector/Combustion Chamber Seal Tool Set - T10133B

You can also buy a kit off of Amazon or similar (link below) or rent a tool kit. Here’s a video on what the kit does exactly, followed by another video using a work-around method. I took the method further and used a zip tie that was wider than the seal, turned it inside out to use the smooth edge, and then used a pair of pliers to help shrink the seals down.

Here’s a kit on Amazon for under $100.

Also, SSSSS5 found that AutoZone has the toolkit and you can rent it from them. It’s tool kit number 8877.

Here’s the Audi OEM injector repair kit which is three pieces per pack (you need eight!); 06E998907C
If you’re an Audi Club member, it’s a 10% discount. Came out to about $126 for a full set of eight. Not cheap. Other Audi kits don’t seem to be compatible. ECS Tuning does sell these too. It’s a wash cost-wise as with my discount, the per kit price was less expensive but it evens out with tax (still a sliver less expensive locally with the Audi club discount).

After you’ve refreshed the injectors, you do not need the special tool to put them back in either. A socket which is larger than the injector but fits on the metal injector support will work. Just tap in softly with a rubber mallet. There’s a cutout in the injector port and that’s space for the electronic plug coming off the injector. So the passenger’s side will point towards the rear of the car, the driver’s side towards the front.

LASTLY, intake manifold “grommets”. You’ll see me mention these in the video and in this thread. They’re easy to loose. The Audi part number is 06E 133 588. These are the small metal/rubber spacers used to secure the upper intake manifold to the lower. They’re cheap so order two or three in advance in case you manage to make one disappear when pulling off the upper intake manifold.

Here’s a blurb from the manual. A hand vacuum pump is pretty inexpensive so I’ll grab one of those.

Edit: After completing the carbon clean, IMO, it’s VERY necessary to have one of these. A simple brake bleeding hand pump works just fine. You can check they work correctly after cleaning as well as after the LIM is bolted down securely.

Carbon clean is a week away. Walnut media is arriving around Friday and I have everything else needed. I plan on doing a full service position clean as I’m going to replace the accessory belt while I’m in there and clean all the heat exchangers (and anything else I find!). Serviced the differential today, both sides, and the transmission is getting a full fluid change tomorrow.

Completely forgot to order locating pins for the service position. Found some M10x1.5 100mm bolts at True Value (Ace in other states). That should probably give me enough room to get a wrench on the crank and hopefully change the accessory belt while I’m in there assuming they’re the right pitch.

Edit: The bolt is an M10x1.5 and the 100mm length is plenty. Honestly the hoses and everything else that you leave attached keep the front end from sliding out further.

I managed to take the front bumper off (super easy) and get the car into service position today. I quit earlier this afternoon but may go back out and remove the upper and lower intake manifold if I’m bored. Otherwise I’ll do that first thing tomorrow morning and then start carbon cleaning.

No real gotchas other than the fuel pump fuse. I pulled #3, 25A, brown fuse block on the driver’s side. Double checked the manual, yep, correct one. Car ran and ran and ran. I finally gave up and shut it off. I didn’t want the car to heat up any further as I needed to drain a bit of coolant. I’ll just wrap the hpfp lines with rags and tons of paper towels. Edit; IMO, the fuel lines depressurize overnight. There was gas in the lines but not under pressure. The return line underneath the lower intake manifold held the most gas so be sure to stuff extra rags/towels under those (one per bank).

Took lots of interesting photos and measured a bunch of stuff. For the life of me, I have no idea how JHM will get a supercharger down low like the S5 kit without a lot of cutting. Anyway, was tons of fun and interesting to get the front end apart. Audi manages airflow pretty well. As complicated as they make everything else, the front bumper and the service position was fairly straightforward.

Lots of carbon. Still going at it. No longer fun.

Here’s a few more images really quick.

Almost clean.

It’s easily a two-day job. If I had a really large compressor and wasn’t shooting photos/video (and had done it at least once before!) I could get it done in a day. I’m at 51,000 miles (about 82,000 Kilometers).

You will need a good amount of mechanical skills and precision due to a few of the “gotcha” items which I’ll detail at some point soon.

I will say this…the weather was spotty, raining at my house, but in other spots it was bone dry and I had a few opportunities to get on it. I feel like the midrange is greatly improved and the top end definitely has more zing. It was noticeable even with the car idling for extended periods and fully warmed up.

Here’s a list of the tasks needed to accomplish this not necessarily in order.
-Bleed off fuel pressure
-Remove front bumper
-Remove undertray
-Put car into “Service Position” which pulls the entire front bumper/radiator assembly forward
-Drain a bit of coolant from the front crossover pipe
-Remove upper intake manifold
-Remove lower intake manifold
-Remove injectors (they WILL come up with the lower intake manifold)
-Install new teflon combustion chamber seals and o-rings on injectors
-Clean the crap out of the injector bores and all mating surfaces
-Clean crap out of the LIM intake ports and flappers
-Replace (at least) the LIM to intake port gaskets
-Carbon clean eight cylinders at 45 minutes a cylinder
-Install injectors, oiling the o-rings and the boss they fit into on the LIM
-Install the LIM (fairly straightforward but a few “gotchas”
-Install the UIM (major pain in the ass)
-Remove car from service position and align
-Re-install front bumper and align
-Re-install under tray
-Crank car a few times to prime system and fire her up
-Add coolant and bleed system if necessary

I also replaced my accessory belt while I was in there and did some cleaning of the heat exchangers.

Just going to post some photo porn and will organize and update the thread as I have more time.

Intake port with divider installed

A big chunk of carbon

If you look at where the valve meets the cylinder wall, you can see gummed up carbon there. That has to be cleaned with a pick. It also collects around the base of the valve guide, particularly on the back side where airflow is a bit more stagnant.

The engine valley and ports fully exposed. If that shot gives you the willies then carbon cleaning is not for you!

One LIM removed, one to go. They’re a total b*tch to get off especially when you’re trying NOT to pull out the injectors. Just go with it. Pull and plan on replacing the seals on all the injectors. No way around it. Poor design Audi.

Take lots of detail shots so you know how everything goes back together. That one torx screw holding down the fuel line separator? I managed to bolt it down to the boss just to the left. And that’s for the LIM (lower intake manifold). I couldn’t figure out why that last bolt wouldn’t go in!

Back side of the UIM (upper intake manifold). There’s one plug, for the driver’s throttle body which is extremely difficult to remove and back on. It’s on the same side as the passenger’s instead of designing a new one with the plug on the outside. Thanks Audi.

UIM underbelly.

Clean fuel injector bores, runner dividers and ports.

Clean bore left, dirty right. Use a gun cleaning kit or order some twisted wire brushes online.

Correct part number for the RS5 injector rebuild kit. It’s three pieces and includes the combustion chamber seal. Not sold separately. A full set ran me about $120 with my Audi Club discount. If you think ahead, you can save about $10 through ECS for a full set (8).

Injector with the old seals removed.

That’s the business end of a shop vac in the foreground with a small piece of clear plastic tubing strapped to it using electrical tape. I could see when the walnut shells were flowing this way. I completely sealed off the rest of the car but found it unnecessary with the port adapter and removed it all. If your’e fairly careful, it’s easy to keep the walnut shells contained.

Clean port dividers!

So the biggest “gotcha” other than the injectors pulling up with the lower intake manifolds is the spacer/grommet setup on the upper intake manifold. I’m experienced and have taken many an engine apart. Maybe I was just tired but I completely zoned out on this little detail.

Here’s a photo of the grommet with the bolt removed.

Now there are 10 bolts, ten grommets and 10 spacers. The spacers are the “gotcha”. When you remove the bolt, DO NOT remove the grommet. It holds the spacer in place. If you remove the grommets, all of the metal spacers will spill out the bottom and into crevices henceforth unknown, undocumented, and not located on any map. You will then be forced to fish around the engine’s V with a flashlight and a magnetic retriever. One managed to fall down the front of my engine and lodge itself on a ledge on the bottom of the car. Sheer dumb luck that I found it.

Chances are, when pulling the UIM up, you’ll loose one or two anyway. I haven’t looked to see if you can get a set separately, but I’d highly recommend that you have at least for or five sets on hand when you pull the manifold. Just in case. Audi lists this as a “decoupling element”.

The part number for the grommets is 06E-133-588

It’s number 4 in the diagram. But it’s two pieces. One is the grommet which is a metal disc with a rubber insert as well as a spacer which is a metal tube with a flat bottom lip. This keeps the torque on the grommet and spacer and not on the plastic portion of the intake manifold. Because of the flat bottom (lip) on the spacer, it does not lift up and out of the intake manifold. It would have been far easier just to allow removal from the top. But oh well. My pain, your gain.

The second potential gotcha can be avoided as well. If you have ACC (adaptive cruise), the manual states it’ll need to be recalibrated if you put the car into service position. I carefully marked the bolts before removal and put the lock (front bumper support/radiator/cross bar) as close to where it was before (easy to do if you pay attention) and bolted it back down. I had no issues with my ACC after.

The third gotcha is the cap for the high pressure fuel pump lines. There’s one each on the lower intake manifold, left and right. The cap can slide all the way down with ease while installing the LIM on the driver’s side. So much so that with the LIM in place, the cap gets “caught” between the LIM and the block and you cannot get it past the block without unbolting it lifting the LIM slightly. So take note of where that cap is before pushing fully down to seat the LIM.

I jacked the car in the air and put it on lifts so I wouldn’t be bending over as far. Made it a bit easier.

With the walnut shells, it’ll be necessary to have the media feeder, compressor and a shop vac. Plus the walnut shell media itself.

I bought a small, really quiet compressor at Harbor Freight. And it really is quiet. The shop vac was easily three times as loud.

I’ll get around to putting a full list together here soon. Had to work the holiday and relatives arriving tomorrow. My turkey day is Sunday :slight_smile:

- - - Updated - - -

I jacked the car in the air and put it on lifts so I wouldn’t be bending over as far. Made it a bit easier.

With the walnut shells, it’ll be necessary to have the media feeder, compressor and a shop vac. Plus the walnut shell media itself.

I bought a small, really quiet compressor at Harbor Freight. And it really is quiet. The shop vac was easily three times as loud.

I’ll get around to putting a full list together here soon. Had to work the holiday and relatives arriving tomorrow. My turkey day is Sunday :slight_smile:

One thing I forgot to mention is I did experiment with nothing but walnut shells and picks, carbon cleaner first, then walnut shells and picks and lastly, walnut shells and picks first, then carbon or carb cleaner at the end. I found the last method, walnut shells, then picks, then more walnut shells followed by either carbon deposit or carb cleaner (two different products). There is a slight dust residue left over with the walnut shells and that helps remove it and leaves the intake ports nice and shiny along with the valves.

Doing the liquid cleaner first seemed to slow down the effectiveness of the walnut shells and it took longer. Using nothing but liquid, brushes and picks, it’s probably double your time per cylinder. I’d definitely coat and soak everything overnight if you do it that way. And have about a dozen rolls of paper towels on hand. You’ll still want a compressor to blow out the ports and/or a shop vac for cleaning purposes. I completely vacuumed the car’s engine bay, the vee, the areas usually not accessible, etc…

Warning: This is a work in progress post. There’s so much material it’ll take me a while to organize it all. I’ll remove this message when it’s complete.

Audi RS5 carbon clean DIY

***I highly recommend you have a factory service manual on hand. I had it in electronic form but also printed out certain sections to have them on hand as a quick reference. Where to get manuals:

Tools needed
(2)M10x1.5 bolts, 100mm in length
-Magnetic retrieving tool (very important)
-Basic socket sets, metric, in 1/4, 3/8 and 1/2" sizes. Audi likes to use 13mm, 16mm and 18mm with regularity so keep that in mind.
-Open end metric wrenches in various metric sizes, particularly 14mm, 17mm, 18mm and 19mm but have a full compliment on hand
-Torx bit set, particularly T25, T27 and T30
-Bit holder socket (1/4" is probably best)
-Triple square set, particularly M8, M10 and M12
-Torque wrench that’ll read down to 10Nm. I bought a 1/4" torque wrench for the small bolts
-Long breaker bar (3/8"). I use the aluminum handle on my jack over a 3/8" breaker bar. This is optional for accessory belt replacement.
-Assortment of power tools. I have a battery-powered drill as well as a small impact battery-powered impact gun.
-Shop Vac
-Air compressor
-25 pounds of medium grit walnut shells
-Harbor Freight portable abrasive blaster kit
-Carb cleaner (three cans sufficed) and not to be confused with carbon cleaner below
-Specialty carbon cleaner of your choice (one can)
-Denatured Alcohol and Acetone
-Pick set
-A few rolls of paper towels
-Shop rags
-Rifle bore cleaning kit (Walmart!) for the injector bores
-A number of good light sources big and small including a small LED flashlight
-Jack stands or a lift
-A gallon of distilled water
-Container to drain coolant into

Links for what I purchased above

A quick note on the compressor I purchased. It’s very small, extremely portable and very, very quiet. That last part was important. I will say a larger compressor with an inline water filter will work faster.

Walnut shells-
Triple square socket set-
Torx screwdriver bit set-
Magnetic bit holder 1/4"-

For lights, I had a few different ones. The coolest by far is the Braun under-hood LED light. It’s round but has hexagonal end caps so you can position it and it won’t roll. In addition, the end caps unscrew to expose a length of attached rope. There are hooks on the end and this allows you to adapt the light to different width hoods. You can even hang it from your garage door rails for an overhead light when needed. It’s also cordless, rechargeable and has a low and high setting. Seems pretty rugged too.

I also used smaller work lights. Not sure if they’d be better on a stand or not.

Audi-Specific Parts
(1) Audi crank adapter tool, part number T40257
(8)Injector Rebuild kits part number 06E998907C
(8)Lower intake manifold to head gaskets part number 079129717B
(1)Accessory belt part number 079903137AG
(1)Gallon of Audi G13 Coolant part number G013A8J1G
Intake manifold grommets if you loose any, 06E-133-588
(1) Coolant line copper gasket N-0138115

Injector rebuild kit-
LIM gaskets-
Accessory belt-

Cliff notes version of all the steps necessary to complete the cleaning
-Bleed off fuel pressure
-Jack car up and put on four lifts
-Remove front wheels
-Remove front bumper
-Remove main under tray like you are changing the oil from
-Drain a bit of coolant from the front crossover pipe
-Go through steps to put the car into “Service Position” which pulls the entire front bumper/radiator assembly forward
-Remove upper intake manifold
-Remove lower intake manifold
-Remove injectors (they WILL come up with the lower intake manifold)
-Install new teflon combustion chamber seals and o-rings on injectors
-Clean the crap out of the injector bores and all mating surfaces
-Clean crap out of the LIM intake ports and flappers
-Replace (at least) the LIM to intake port gaskets
-Carbon clean eight cylinders at 45 minutes a cylinder
-Install injectors, oiling the o-rings and the boss they fit into on the LIM
-Install the LIM (fairly straightforward but a few “gotchas”)
-Install the UIM (major pain in the ass)
-Hook up all the coolant and electrical lines that were removed
-Install a new accessory belt (easier with two people but can be done with one)
-Remove car from service position being careful to align it back up to where it was previously
-Re-install front bumper and align
-Re-install under tray
-Crank car a few times to prime system and fire her up
-Add coolant and bleed system if necessary

LIM=Lower Intake Manifold
UIM=Upper Intake Manifold
LPFP=Low Pressure Fuel Pump
HPFP=High Pressure Fuel Pump

Step One
You’ll need to lower the fuel pressure in the rails prior to and after the high pressure fuel pumps. On the RS5, you’ll need to pull the 25W fuse for the LPFP. It’s the middle fuse panel, third from the top. Start the car first, then pull the fuse. Rumor has it, the fuel pressure will eventually die enough that the car dies. Mine ran and ran and ran. I gave up and shut the car off and moved on. I didn’t end up opening the fuel lines for another 8-10 hours (next day) and there was fuel but none of it was under any real pressure. Your results may vary. Jack the car up and put on four jack stands using the reinforced seam weld jack points. I use a jack puck and jack stand protective rubber covers. I chose to jack the car up so I would not be bent over as far. I’m 6’3" so this makes a difference. Adjust to your comfort level. It will make it slightly difficult to reach some of the plugs on the back of the engine. Keep that in mind and adjust the height accordingly.

Step Two
Loosen the front wheel lug nuts. Just a tad so they can be easily removed after the car is up in the air. Jack the car up and put on four jack stands using the reinforced seam weld Audi-specified jack points. I use a jack puck and jack stand protective rubber covers. I chose to jack the car up so I would not be bent over as far. I’m 6’3" so this makes a difference. Adjust to your comfort level. It will make it slightly difficult to reach some of the plugs on the back of the engine. Keep that in mind and adjust the height accordingly.

Step Three
We’re now going to remove the main under tray/splash shield. You will also want to remove the lock carrier cover (big piece of plastic that covers the intake ducts up top) both intake assemblies as the ducts are bolted down to the lock carrier. I have the Eventuri intakes so it’s a bit easier than OEM. No need to remove the coils or plugs as I’m assuming the injectors will come out.

This is an exploded view of the under tray and a few other components. Numbers 8, 15 and 18 all come out as one piece. The duct, #9, is held to the under tray by two bolts which must be removed. Otherwise you’ll pull it out along with the under tray.

You’ll want to remove the five bolts, T30 torx if I remember correctly, in either wheel well. See diagram.

The main under tray is primarily held in place by five M8 triple square bolts (they may be M10, can’t remember) and five T30 torx bolts at the leading edge.

The factory diagram is different from my car but if you take a careful look it’ll be obvious what bolts need removing and which ones don’t.

Don’t forget the two bolts which hold the duct to the under tray.

With the rear-most triple square bolts removed, the pan will drop straight down at the back. You’ll still need to untangle it a bit from the rest of the bodywork to fully remove it.

Step Four-Front Bumper Removal
We’re ready to remove the front bumper now. It’s fairly straightforward, being held on by two 10mm bolts on either inner fender, two T30 Torx bolts near the top of the grille and a few clips. Additionally, there’s a forward under tray which is bolted to the composite radiator support structure from underneath.

To remove the bumper under tray from the radiator support bracket, loosen the four T30 bolts.

Remove the lock carrier cover in the engine bay (it covers the gap in between the bumper and the radiator) which is held on by the four plastic rivets.

We’ll want to remove part of the wheel well lining to get access to the two 10mm bolts securing the bumper to the fender. Since we’ve taken off the five T30 torx bolts earlier, there are only a few fasteners needing removal to pull the lining back far enough to gain access to inside the fender.

By removing those two fasteners, you’ll have enough room to pull the liner back and gain access to the two bolts and a clip securing the front bumper to the fenders. It’s the same on both sides. The clip at the bottom can be partially pushed out with a long, flathead screwdriver. The two bolts are 10mm and are fairly easy to get off.

Next is an emotionally difficult part…grabbing the bumper just below where it meets the fender in the wheel well, pull towards you gently but with some force. The bumper is flexible and held to the side with clips. It’s not as bad as it sounds and it’ll unclip fairly easily.

There are two more bolts to remove, on either side of the grille up near the lights. Both are T30 Torx. Once you remove those, the bumper will not fall off. There are two more clips, on either side of the grille which necessitate you pulling forward to release them. The entire bumper will come off at this point.

Step Five-Service Position
Putting the car into service position by moving the lock carrier (entire radiator assembly) forward is fairly easy at this point. It’s held on by three 16mm bolts. You’ll be replacing the bottom outboard bolt with the M10x1.5 100mm bolts and that’s what the entire lock carrier will slide out on.

First you’ll want to drain a bit of coolant. I drained approximately two liters and it served my needs. You drain a bit as there are coolant hoses connected to the UIM and you’ll want to remove one connector in between the coolant reservoir and the radiator.

On the underside of the car, in between the oil pan and the radiator support is the lower coolant cross pipe. It has a plug which can be loosened by a T30 Torx bit. It was on there firmly and the plug is supposed to be replaced as it has an integrated washer. I haven’t figured out the part number for that plug yet so I snugged back down firmly when I was done. Loosen it and coolant will come pouring out so have a appropriate container to catch the coolant. Do not reuse the coolant.

With the coolant drained and the plug reinserted so it’s no longer leaking, it’s time to start unplugging various connectors and at least one hose. I removed many hoses and connectors in the front end which I believed would be necessary in order to put the lock carrier in service position and ultimately, it was all for naught.

The one coolant line I felt necessary to remove was the line leading from the coolant overflow tank to the top of the radiator on the passenger’s side. Because the lock carrier moves forward, it would force that line to bend. Yes, it’s rubber but it has turned hard with time and I did not want to put any stress on the line. It’s simple to remove, simply pull up on the metal clip with a flathead screwdriver and then push the connector towards the rear of the car and off the radiator nipple. Treat it gently.

There are two electrical connections which must be undone. The first is the plug for the parking sensors and the plug for the Homelink if your car is so equipped.

The parking sensor plug is the most obvious, it’s right up top in between the radiator and bumper support.

The second electrical connector for the Homelink is harder to see and down in between the bumper support and the radiator. Unplug it and you’re done. Nothing else needs to be unplugged. Not the lights, no other radiator hoses, nothing.

Disconnect the hood latch cable. It’s fairly easy and you won’t have to re-adjust anything when you put it back together. It’s in the engine bay on the driver’s side attached to the main support beam. It’s held on by two clips. You’ll need to remove the entire rectangular assembly from the clip and then pull on the driver’s side of the cable to release the flip-open cover. Once open, pull the driver’s side end out of the mechanism.

Now that everything has been disconnected, it’s time to unbolt the lock carrier and install the longer M10 bolts so we can slide everything forward. In addition to the three bolts for the lock carrier, there are two support bars that run diagonally from the outer corner of the front bumper composite support to the front subframe on the bottom of the car. There are two bolts you’ll be removing, both are 13mm if I remember correctly. A short socket is fine as they’re easily accessed.

The lock carrier bolts are 16mm and the long replacement bolt is imperial but I think I got away with an 17mm socket. A short socket is fine but you’ll want a long extension, about 6-8". I used my small impact gun to loosen and remove them. They’re not on there very tight.

You’ll want to do the BOTTOM OUTSIDE BOLT FIRST. Once you remove this bolt, install the longer bolts and then remove the other two, one below and one up top. If the top bolt falls out of the socket, just use your magnetic tool to retrieve it.

There are two last bolts to remove up top along the top of the bumper/radiator support, one on either side of the car. Both are T30 torx.

Once you have everything disconnected or removed and the lock carrier resting on the longer bolts, you’ll simply pull forward on the crash bar. One tip, I used some dry silicone lube on the bolts to help things slide forward. I don’t really think it’s needed or if it actually helped as it was fairly easy to get the lock carrier to slide forward. It won’t slide forward very far though as there are many hoses, coolant and oil line hoses, that basically spring it back. You only need a bit of room to get a tool onto the crank (more on that later). You will be disappointed in how far forward it moves. It is what it is.

Here’s a decent shot illustrating how much room you’ll have at the front with the lock carrier in the service position.

With the car in the service position, it’s now time to remove the upper and lower intake manifolds.

Here’s a video for the service position how to;

Carbon cleaning part 1 now live…

Carbon cleaning part 2 is now live…

Upper Intake Manifold Removal

The first round will essentially be unplugging a whole lotta stuff. A little tech tip if you do not trust yourself, take painter’s tape and each connection that you separate, whether it be electrical, coolant hoses or otherwise, mark each side with the tape and write a corresponding letter on the ends that connect together. I will say this…most of the lines and connectors are routed as such that it’d be hard (but not impossible) to mix them up so use common sense. And take photos with your smartphone for reference!

We’re going to start at the back with the PCV valves. They’re the two big round things in between the throttle bodies. A single torx screw holds each one on. The end of the tube connects to the breather ports on the valve covers. Pinch that end off first, then remove the two bolts. While you’re back there, you’ll need to remove each and every hose that’s attached to the manifold. Pliers work fine.

What it looks like in real life. Note, the FSM left off a few hoses so again, use common sense and look at everything. It’ll be obvious what needs to be removed.

There is one vacuum line which connects from the passenger’s side intake elbow to the PCV system elsewhere. The UIM has a metal grab handle (or support depending on how you look at it) and this vacuum line literally loops around it and prevents you from lifting the UIM up and off the engine. You’ll need to snake that vacuum line through a bundle of hoses and wires and away from the back of the intake manifold. I’ve outlined the hose in red. By the time you go to remove this line, the PCV valves and other hoses should be off making it much easier.

We’re going to unplug the throttle bodies next. Obviously there are two throttle bodies and there are naturally two plug connectors. Each connector has a little pink tab which you pull straight back with the aid of a screwdriver. Once you’ve unlocked the connector, it’s easy to get off.

Here’s the photo from the FSM. The arrows are the throttle body (throttle valve) connectors and the 1 & 2, in blue are the evaporation hoses which must also come off.

Real life, passenger’s side. The plug on the driver’s side is inboard, not on the outboard side. It is quite hard to get to and disconnect so be patient with it.

Most of the connectors are on the back of the intake manifold but there are some on the front. Looking at the FSM diagram, #1 are two vacuum lines that come off fairly easy. #2 is the MAP sensor plug and #3 is another vacuum line. Disconnect all of them. #1 is under the manifold and you can pull them off as you lift the UIM up.

With all the lines disconnected, it’s time to remove the ten UIM bolts (T30 Torx) which secure it to the two lower intake manifolds (one for each bank). Loosen them in a cross pattern, 1-10 as listed below. THIS IS VERY IMPORTANT. DO NOT REMOVE THE METAL GROMMET BELOW THE BOLTS. LEAVE THEM IN PLACE.

Pay careful attention. I’ve circled #4 and #5 in the diagram below. Five is the bolt. #4 is actually two pieces. One is the metal/rubber grommet visible underneath the bolts you just removed. The second is a metal spacer with a lip on one end. Due to that lip, it cannot be lifted out the top. It’ll only come out the bottom. If you remove all the grommets and lift the intake manifold up, those ten small tubular spacers will go tumbling every which way into the engine’s vee and perhaps further, never to be seen again. Leave the grommet in place. In fact, before removing the UIM, inspect each one closely and if need be, seat the grommet even further by pushing down on it so it’s fully engaged with the spacer.

Here’s a photo of the grommet with the spacer still installed on the UIM. The second photo is a closeup of just the grommet. Note the middle is rubber and is what “grabs” the spacer and holds it in place. No, it’s not very secure which is why you need to make sure it’s fully seated around the spacer.

Here’s an UIM dowel spacer that fell very close to an intake port

Once all ten bolts are removed, look over all the connections and make sure you have anything necessary removed. It’ll take a bit of force to separate the upper from the lower as the gaskets “seal” with heat. So it’ll come off suddenly. Be prepared. Once you’re able to separate it from the LIM, double check everything is disconnected. The harness on either side of the UIM will prevent the manifold from lifting up so you’ll have to wiggle the UIM up and out from underneath the harness, the engine hoist bracket and a few lines. If you haven’t disconnected the vacuum lines at the front/underneath the UIM, do so now that you have more space. And watch the spacers/grommets! If one falls off, at the very least, listen and look to see where it goes. If it falls into the valley, you’ll be removing enough that you’ll be able to find them down there.

You’ll be left with this;

Lower Intake Manifold Removal

The LIM is difficult to remove for one reason alone; the injectors. Mine were “stuck” in the LIM fuel rail and as such, when I pulled either side up, no matter how I tried, the injectors would go with them. No way around it. With 50K on the clock, those OEM o-rings had pretty much sealed themselves to the injector bungs.

If you’re prepared for the above with rebuild kits for all eight injectors, it’s relatively straightforward. It still necessitates a good deal of force to pull each LIM up and off the heads. Keep that in mind.

Here’s an exploded view of the LIM. Note, ALL of this comes up together as one piece except for the fuel return line (#13)

We’ll need to remove the vacuum chamber in the vee of the engine. It’s held on by three (two on the left, one on the right) T30 bolts to a bracket. You’ll only need to remove two vacuum lines; the smaller one coming off the top of the chamber nearest the rear of the engine as well as one connected to the front via a solenoid. You’ll need to unplug the solenoid as well.

Closeup shots of the bracket it’s bolted to. Note how it’s situated when you remove the vacuum chamber.
Driver’s side

Passenger’s side

With the vacuum chamber removed, this is what you’ll see. Now is a good time to fish out those dowel spacers if you dropped any in the valley.

Take lots of photos and notice how the fuel line spacers are situated and where.

Remove both fuel return lines. Make sure to stuff plenty of rags underneath to absorb the fuel that will spill out. There’s one for each bank and if I remember correctly, they were 14mm (or 17mm) nuts. They’re not on tight and you can mark them with a sharpie to make things easier and not over tighten them when it’s time to reassemble everything. It’ll make it easier if you unplug all of the injector plugs prior. Note the passenger’s side injector plugs point towards the rear and the driver’s side towards the front.

Remove the high pressure fuel pump lines. Stuff a rag underneath although I did not have any fuel come out of mine. Again, mark the nut with a sharpie so you don’t over tighten them. There’s two lines on each side. Once those are loosened, remove all the fuel line brackets pictured earlier to give you wiggle room.

There are several electrical connectors on the passenger’s side LIM towards the front which need disconnecting including the fuel pressure sender pictured below as well as one on the vacuum actuator for the intake runner flapper system.

There’s one matching electrical plug on the driver’s side near vacuum actuator for the flaps which needs removing. It’s number 5 in the exploded diagram. One on each bank.

With all of the connections removed, it’s time to remove the bolts holding the LIM to the head. You’ll be removing them in a cross pattern. The top side bolts are longer and have a different head shape from the bolts along the bottom. Make mental note. Both are T30.

With the bolts, fuel lines and electrical connectors removed, grab the LIM by either end and lift straight up. You may need to use a small side-to-side wiggle motion to gently rock the injectors loose from either the fuel rail bung or from the injector ports in the head. You may get lucky and not all of them will come out. It will take a good deal of force!

Shot of both LIM’s after removal. Old LIM to head gaskets pictured in background. The yellow/green gaskets up top are also replaceable but extremely expensive. Don’t damage them. They’re like $25 each. Ridiculous. FSM says to replace but they’re fine to reuse.

Closeup of one bank after the LIM was removed. The injectors are still in there but they did come up slightly, enough that I knew I’d need to replace the seals.

Overall of the engine valley with the LIM removed.

The next step is to remove all eight of the port dividers in the intake runner. Just use a pair of thin or needle nose pliers. Grab each side by the “D” shape, wiggling the divider and going from one side to the other as you pull up. Pull all of them and soak in some sort of carb or carbon cleaner. You’ll clean them off and reuse them. The protruding dimple faces down when you go to reinsert them back into the intake runners…

I took the injectors and punched holes in a cardboard box, labeling each injector so I know which one goes where. No real “need” to do this but what the heck. The new gaskets are already on (top o-rings are blue in the rebuild kit, the originals were brown).

New LIM to head gaskets but more on that later.

Gratuitous shots of the LIM just because. How often do you actually see them?

Dividers cleaned and ready to be installed after the carbon cleaning.

Carbon Cleaning
I know this is the step you’ve been waiting for. In the photo below, I’ve taped everything off except the port I’m cleaning. Additionally, I laid drop cloth in all four directions. In the end, the drop cloth, if you’re careful, isn’t necessary.

IT IS necessary to tape off the ports you’re not cleaning and TAPE OFF THE INJECTOR PORTS TOO!

After I was done cleaning a port, I’d tape it back over and mark the tape with an X.

With the car in the service position, there’s enough room to get a 3/8" breaker bar down there. I’d originally purchased a specialty tool for Audi which supposedly fits in the crank’s snout. See pic.

Well, it does not fit. In fact, there’s nothing but a bored out cone in the center of the crank. No threads, nothing. Somehow I had the wrong adapter. What you actually need is part number T40257 which fits over all the harmonic damper bolts. Here’s one place to get it but they’re on eBay as well;

I was in a pinch since I didn’t have the proper tool. The harmonic damper bolts are M8 triple square bolts. By inserting the bit in just one, you can easily turn the engine with the injectors removed. It was actually shocking how little friction there was. To be safe, I’d get the adapter. It’s like $35.

Shot from the FSM. Just ignore the arrows and other bit, just showing you how the adapter fits in there and what the crank end looks like.

Once you have your bit and breaker bar attached, rotate the crank until the valves in the cylinder of your choosing are closed. Just watch the valves aided by a flashlight as you rotate the crank slightly. It’ll be obvious when they’re closed and they’ll stay closed for a decent sized duration of crank rotation. Another little tip…usually one or two other ports are fully closed. This’ll save you time rotating the crank.

Test that they’re closed by putting a bit of gas in the port with a syringe, carb cleaner even. If, after a minute or two, the gas is still in there, you can begin carbon cleaning with the walnut shells.

My logistical modus operandi was as follows:
-Blast with walnut shells moving the nozzle around to try and get all areas of the port.
-Flip the adapter 180 degrees and repeat.
-Remove the adapter and inspect
-Go over the ports and valves with the picks, loosening carbon that’s stuck in the crevices of the valve seat as well as behind the valve guides (two worst spots)
-Put the adapter on, switch to the air nozzle, blow compressed air in and suck the chunks out
-Blast again, repeating the 180 degree rotation
-Pick at everything again, blow out with compressed air
-Blast once more and then blow out with compressed air
-Spray in carb cleaner (not carbon deposit cleaner) and wipe the ports out with disposable paper towels. Rinse and repeat until the runner walls and valves shine.
-Tape the port back over, mark with an X and move on to the next one.

Here’s a short teaser video of what the process looks like

Once you get through with carbon cleaning the ports, we’ll want to take several preparation step before reassembly.

Since the injectors are out, the injector ports in the head need to be cleaned and spotless. There is a factory service cleaning kit that you can probably track down or even purchase small diameter twisted wire nylon or soft brass brushes. A rifle (gun) cleaning kit also works. I bought mine at Walmart for about $7.

I did clean out the bores by shop vac and hand first to remove any grit. Using the brushes and carb cleaner left the injector port walls with a mirror finish. I also cleaned the smaller bore where the injector nose/seal sits.

Clean injector ports and the dividers reinstalled.

With the injector ports cleaned, plug them up with some paper towel so nothing falls in them. Make sure the rest of the mating surface between the head and where the lower intake manifold sits is completely clean. Wipe it down with your cleaner of choice and finish off with denatured alcohol. Spotless is ideal.

You can also re-install the port dividers. Remember, the dimpled protrusion goes on the down side.

To R&R the injectors, you’ll need the rebuild kit which consists of a new teflon seal, a top o-ring and a split ring shim. You can only buy them as a kit. Each kit contains these three elements so you’ll need eight kits. ECS does sell the kit. Alternatively, if you’re an Audi Club member, the 10% discount actually makes it a slightly less expensive alternative. My dealer does not stock the kits. I had to overnight them from the Fort Worth distribution center. It was an extra $14. Won’t break the bank but do plan ahead and have the kits prior to pulling the injectors. Worst case scenario, you can send back unused kits if you manage to have an injector or two that decide to stay put.

The kits. Note they’re made in Italy.

Here’s an injector prior to having the new kit put on. The original top o-ring is brown, the new are blue. The shim and the teflon seal look the same.

To get the old teflon seal off, use a small utility or hobby knife to simply cut them off. Be gentle as you don’t want to gouge the injector with the blade. The o-ring comes off easily with a small pick or even your fingers.

Here’s an exploded view of all the injector components from the FSM.

The tricky part to the injector rehab process is getting the teflon combustion chamber seal installed. The seal itself is malleable. It’ll stretch and you can also compress it. As it comes out of the package, the seal’s inside diameter is smaller than the outside diameter of the the injector’s tip. The seal sits in a groove with a smaller outside diameter than the shaft. To get the seal onto the injector, it needs to be expanded. The best way to do this is with a cone.

Here are some excerpts from the FSM using the specialty tool which costs about $200. I’d recommend purchasing the tool but it can be done without it if you’re careful and detail oriented.

First step, slide the seal onto the expansion cone.

Second step, push the seal onto the expansion cone further with other half of the audi tool using a twisting motion.

Third step, line up the expansion cone and twist with the other half of the Audi tool until the seal slides over the end of the injector and into the groove.

With the combustion chamber seal in the injector’s groove, continue to twist the tool and it’ll shrink the seal back down.

I had a bit of luck rigging up my own kit. I had an old brake bleeder I’d pulled out to use the vacuum pump to pull back the flappers on the LIM. It included a number of adapters designed to fit various hose sizes. The adapters were cones, made of a very hard, smooth plastic. It almost has a silky feel to it if that makes sense and a very low coefficient of friction. Since it was a long cone, I just cut it at the point where it was the same size as the end of the injector. Perfect! I also had a small plastic cylinder that was just the right size to push the seal on and expand it. Once you get to a certain point, you can actually do it with your digits. I wore clean latex gloves when handling the seals.

Here’s the cone I used, next to a guitar pick for size reference. Worked like a charm.

Now I did not take any photos of me shrinking the seals back down as it’s a two-hand, delicate job and I wanted to concentrate. I took a properly-sized zip tie (same width as the seal) and reversed it so the smooth side was on the inside. I shrank it down so that it still fit over the seal and then used a pair of pliers to press against the outside of the zip tie and worked my way around the outside of the seal. It won’t completely shrink back down but it was enough that the injectors went in easily (with a bit of pressure which is normal) and I’m not experiencing any issues.

I’m a sticker for doing things the right way and I honestly recommend getting the tool. I was in a bind, not knowing how easily the injectors come out and it caught me unprepared. Live and learn. There were enough people online that do it with the zip tie method that I felt comfortable doing it that way.

One you have the injectors rehabbed, insert them back into the injector bores. DO NOT PUT ANY LUBE ON THE INJECTORS! NOTHING ON THE TEFLON COMBUSTION CHAMBER SEALS. VERY IMPORTANT!

The injectors should slide in 80% of the way and it’ll require a bit of careful force to push them in all the way. Be gentle. Take careful note of the cutout in the head for the injector electrical connector and make sure it’s oriented in the right direction before trying to push it all the way in the bore.

Closeup of an injector almost seated in the bore. Find a socket that sits flush with the support ring and use a rubber mallet to softly tap the injector in place.

LIM Reinstallation
With everything clean and the injectors in place, it’s time to reinstall the LIM. Make sure you’ve lubed the injector o-rings. I also put a thin coat on the injector bungs in the lower intake manifold.

You’ll want to clean out the LIM runners and flappers a bit as they can become caked with oil over time and stick open/closed. Clean them and then make sure they’re functioning properly with the vacuum pump. Clean the green, LIM to UIM gaskets on top with denatured alcohol.

The last thing you’ll want to do before installation is install the new LIM to head gaskets. They’re the red ones on the bottom. They’re stuck in there somewhat but they come out fairly easy with a small pick. Install the new ones by pressing them into place and you’re good to go.

With the injector o-rings lubed, position the LIM and line up the injector bungs in the LIM with the top of the injectors. Before you press down, make sure the high pressure fuel line nuts are up where they should be. They can slide all the way down to the LIM and get pinned between the LIM an the block.

Attach the vacuum pump and open the flaps fully.

With everything lined up, push down on the LIM until the bottom sits firmly on the head. Slip the nine bolts into their respective homes, the long bolts on top, the shorter, button head bolts on the bottom.

The tightening sequence is in a diagonal pattern in stages up to 9Nm.

At this point there are no real gotchas except for the spacer/grommets on the upper intake manifold. Just take it slow as you put everything back in place. The vacuum hoses are all shaped so it’s fairly obvious where they go.

With both LIM’s in place, make sure all the fuel lines are routed correctly and loosely place the fuel line separators around the fuel lines and bolt them down loosely so you can still move everything if needed. Once you have everything installed where it should be, tighten the fuel fittings. These include the return line on the bottom of the LIM (both sides) and two on each high pressure fuel pump. You do not have to crank them. In fact, do NOT crank them. Torque all of the fuel fittings to 25Nm (18ft. pounds). That ain’t much.

With the fuel lines tightened, bolt all of the fuel line separator brackets down securely. There’s four of them.

Plug the injectors in as well as all of the electrical fittings you can reach now and probably not later. This includes the fuel pressure sensor, passenger’s side at the front side of the rail. It’s easy to miss and/or forget.

With all of the electrical fittings in place, re-install the brackets for the vacuum chamber. If you’ve forgotten which way they go, take the two brackets (one on each LIM) and the vacuum reservoir and line everything up. It’ll be obvious which way they go in as the vacuum chamber sits snugly in a space within the engine’s valley. Things can only go in one way.

With the brackets in place, line up the vacuum reservoir. Check to see which vacuum lines need to be plugged back in before fully securing.
Here’s a photo from earlier with the reservoir in place.

Check all the vacuum lines and electrical plugs at the front of the engine in between the two LIM banks. Make sure everything is attached properly otherwise you’ll be pulling the LIM again to find out what you left off. Not fun.

Check ALL the plugs and vacuum lines once more. Make sure everything is on securely. At this point we’re ready to re-install the UIM.

Torque specifications (two steps)
1-Tighten bolts 1-10 in order listed to 8Nm
2-Tighten bolts 1-10 in same order to 11Nm

First things first, clean the mating surface for each intake runner on the bottom of the UIM. You can use denatured alcohol. Resist ANY urge to unbolt the upper and lower portions of the upper intake manifold to see what’s inside. I have a feeling it’s sealed and those seals would not be easy to replace. So tempting though.

Torquing everything down correctly is the easy part. The hard part is getting it back in with all the spacers and grommets intact. I found the wiring loom running in between the heads and the intake manifold to cause interference. You’ll also need to loop the passenger’s side PCV hose back through the handle/support brace on the rear of the UIM after you get it semi-situated and in place.

With the spacers and grommets, just make sure they’re pressed in place good and tight and make a concerted effort to not bang the UIM on anything or jar it excessively. It’ll take some fiddling and patience but it will go in.

Be sure to plug in the driver’s side throttle body while you can still move the UIM around. Makes things much easier.

After installing the UIM, go over all of the various electrical, coolant, vacuum and PCV connections on the back of the manifold and make sure they’re securely attached and the clamps are all in the proper location. Do the same for the front of the UIM.

For what it’s worth, in this diagram, I never removed the #3 clamp which is the hose that loops around the UIM support bar. It’s easier to just snake it through everything.

Front vacuum connections.

Some of the connections on the rear.

Push the PCV pressure regulating valves back on and bolt them down to 4.5Nm. Re-attach the other end to the top of the valve cover.

With the UIM installed, and a bit of time on your hands, I’d suggest changing out the accessory belt.

1 Like

Ok this thread is now fully updated with all the photos and videos attached. Lemme know if anyone sees any issues.

Thanks For this Detailed DIY Ape!
It’s highly intimidating, this project and from the DIY. Especially since I had trouble with just the down pipes :joy:. I plan on getting this done soon so I’ll look into this page closer. The car is at 46k so maybe within the next 10/15k miles.

Yeah it’s a about that time for you. It isn’t super technically complicated but there is a lot that can go wrong so best to have someone else do it if you have doubts.

I do think I found a way to do this without putting the car into service position and using the starter to turn the motor over. Looking to see if I can wire a remote starter into the OEM harness where the starter button goes. They have a long enough lead that you can run it out the window and be looking down at the valves when you hit the button quickly to rotate the motor a bit. Just disconnect the fuel system (you pull the fuse on the LPFP anyway!) and you’re golden. Not quite as “exact” as using the crank tool and a breaker bar but the valves stay fully closed for a good deal of time during the crank rotation.

Well I have this Thread to refer to and I’ll need a bottle or 2 of “Focus Factor” tablets in addition to labeling every part if I decide.

Go for it i did and with Michel’s guide i got it done and its never missed a beat since, just take your time and label things and take photos to remind you of where things go and you’ll be fine.

Also Michel if you manage to work something out to rotate the crank via the start button let me know i would be interested in having one for my car :grin:

Will do. It’d require pulling up the center console and the starter button but it’d plug in and be FAR easier than putting the car in service position!

That’s great thank you Michel :blush: it will defo be easier than putting it into the service position and it will save time bonus !!

Our PCV valves seem to be powered by a stronger vacuum than that of for example the v8 S5 (completely different design). A wild guess is that Audi tried to mitigate the build-up. In other words I would ensure to have good working PCV valves. It does seem that cylinders 2-3 and to some extent 6-7 get the bulk of the PCV driven build up.

This leads me to conclude that preventative maintenance using spray cleans can also exponentially help alleviating the problem by removing the build-up that comes off easily but slows the airflow down. That will also cool down the valve head a bit more.

I was finally able to replace both PCV’s on my car. I made a guess as to which one was bad and guessed wrong sadly…even switching the “good” diaphragm to the bad side didn’t help. I know others have experienced a small pinhole crack in the hoses themselves. I tried to wrap mine using electrical tape but no go. Didn’t change/alleviate the horrible whistling.

Sadly, the new valves did not improve my idle situation. It improves as the car warms up so I’m going to take a look at my JHM exhaust, specifically the V-bands on the downpipes section. I think they’re leaking when cold and seal up as they heat and expand, leading to air being sucked in and throwing off the 02 readings.

The whistle noise disappeared at least then with new PCV hoses?