How-To: C6 S6 Intake Manifold Removal & Carbon Clean

A6 All/ S6 All
#1

Hi all,

Trying to get this down while it is still fresh, so this will be a work-in-progress.

First - here are the tools you will need:

  • 3/8 or 1/2" drive ratcheting wrench
  • 1/4" drive ratcheting wrench
  • 1/4" Drive Torx T30 (picture later)
  • Long bit Torx T30 (I used 1/4" drive - picture later)
  • Short (normal) bit Torx T30 (I used 3/8" drive)
  • M8 Triple Square/12 Point
  • M10 Triple Square/12 Point
  • 10mm Wrench/Spanner (stubby is better)
  • 14mm Wrench/Spanner
  • 17mm Wrench/Spanner
  • Needle Nose Pliers
  • Flat Screwdriver
  • Precision (tiny) flat screw driver (for clips)
  • Extendable magnet

Before you start - repeat the following 10 times: ā€œI will not drop any screws.ā€ I havenā€™t (yet), but itā€™s not like an old Nissan - every screw is important!

Another thing to note is that a lot of these screws are aluminium, so be sure your bit is well seated, that thereā€™s no debris in the screw head, and use lubricant before excessive force. If you do strip one, you can hammer the next size Torx into the hole and the material is soft enough to allow a new imprint to be made.

Give yourself about 2 hours.

Step 1 - Take off engine covers. One at the front, one at the back. Remove intake pipes between manifold and air filters. (NOT PICTURED)

Step 2 - Unclip the wiring harness on the left side. Unclip the two clips circled in red. You donā€™t need to remove the ground wire circled in green. The two arrows point to clips attached to the fuel lines. Gently pull these off. Lift the wiring harness over the fuel pump to the left side and leave there.

http://i57.tinypic.com/33ber9k.jpg

Step 3 - Do the same on the other side. There are no fuel line clips on the right side.

Step 4 - Remove the PCV vent hose from the left hand side (squeeze and pull). You need to remove it from the valve cover and from the oil separator. Move the hose out of the way. You can leave the right side connected. Put a rag or something to block debris from going into the opening in the valve cover.

http://i62.tinypic.com/16i9qgh.jpg

Step 5 - Remove the valve/hose. Squeeze the clamp with the pliers and pull the hose up.

http://i59.tinypic.com/2hxa7gj.jpg

Step 6 - Remove the ā€˜air distribution housing.ā€™ There are 8 Torx T30 bolts holding it to the manifold. You will also need to remove the bracket connecting the oil separator to the right hand side throttle body. Remove the two M8 12-pt bolts on the throttle body and the Torx T30 on the oil separator.The housing should now lift away. It may be a good idea to replace the bolts onto the throttle body so you donā€™t lose them.

http://i57.tinypic.com/2cej0hf.jpg

Step 7 - Remove the oil separator. Thereā€™s very little clearance between the firewall and the oil separator, so this is where you will need your 1/4" ratchet and 1/4" drive Torx T30. Remove the bolts (be careful not to drop the bottom one), and pull/push the oil separator towards the firewall to remove it.

http://i58.tinypic.com/2nl5kb6.jpg

Step 8 - Fuel lines. The factory service manual says to remove the fuel lines and the fuel pumps, but I found this wasnā€™t necessary. Nonetheless, you must remove one line and loosen the others in order to free the manifold. Weā€™ll do this step now so you can let the fuel drain out while you do the rest. I was expecting these lines to be under high pressure, but they werenā€™t. Put a rag around the connection as you loosen it in order to soak the fuel. When you do the rear connection, be aware that more fuel will come from here than from the pump connection.

http://i62.tinypic.com/efi8t2.jpg

http://i60.tinypic.com/2v1p4t0.jpg

Now loosen the two lines on the left hand side, at the pump only.

Step 9- Now move to the front of the intake manifold. Remove this little hose and move out of the way.

http://i59.tinypic.com/24zeu68.jpg

Step 10- Remove the little module at the front left of the manifold. I donā€™t know what this thing is, and canā€™t find it in ETKA - some sort of vac sensor - someone will educate me! Unplug the connector, the two hoses, and then remove the bracket it is attached to. One 10mm bolt and one Torx T30 hidden underneath. To remove the 10mm nut, use the stubby wrench, rather than a socket. Using a socket will cause you to foul the hose barb sticking off towards the right, and you donā€™t want to break it.

10b - remove the engine lifting bracket. Otherwise this will foul the manifold when you try to remove. 2x Triple square/12pt M10.

http://i60.tinypic.com/2lvl6y8.jpg

Step 10 - Remove the wiring harness plugs from the three actuator motors, and two actuator position sensors. I had the advantage of having already removed the radiator, so this was easy when you looked from underneath. This may require small hands to complete without the radiator out.

Step 11 - Time to remove the manifold. Up until now you could remove all the Torx with the shorter type, but you wonā€™t be able to get to all the manifold bolts with it. You need a longer type - I used a Blue Point BLPTL1430:

http://buy1.snapon.com/catalog/objects_lg/images/BLPTL1430.jpg

Itā€™s a 1/4" drive, but I just adapted to 3/8"

You will need to move the fuel lines around slightly to get clear access to the manifold bolts. There are 12 of them.

Loosen all the bolts and remove them with your extendable magnet. It will be hard to get to some with your fingers, and you may need a friend to wiggle the manifold and fuel lines to help you free a couple of them. Be careful when removing the rear screws - DO NOT DROP THEM. The rear left one has the highest danger of dropping into never-never land.

Slide the manifold forward slightly, taking care not to damage the gaskets if you plan to re-use them. Lift from the right side and it should come out.

YOUā€™RE DONE. If youā€™re lucky like me, you may find some little plastic gifts left for you in the intake runners!

http://i59.tinypic.com/2wh4dy0.jpg

Part 2 will include the carbon cleaning, once Iā€™ve done it!

-P

#2

Great writeup!

The intake manifold removal/inspection and the carbon clean are two things that are almost guaranteed to have to be performed on every S6 during its lifetime. So, having a DIY for these will be very helpful to fellow S6 owners.

#3

LINK TO UPDATED THREADS FOR INTAKE REMOVAL

http://audirevolution.net/forum/index.php?topic=3950.msg116391#msg116391

http://audirevolution.net/forum/index.php?topic=4000.0

That was a really great right up. Very helpful. The big question is how did you get to the back bottom bolt on here

http://i58.tinypic.com/2nl5kb6.jpg

I know you bought a new intake manifold. Any plans on taking the old one apart to see what all happened inside.

#4

You can get that one also with the 1/4" Drive ratchet and T30 - just hold the back of it with your thumb. The screw isnā€™t on the underside pointing down; itā€™s facing the same way as the top one. Very easy to drop that screw as well!

I also didnā€™t clarify that the Oil Separator is still connected to the block by the drain hose, so you donā€™t remove it completely, rather you just remove it from the manifold.

I did crack open the manifold today, and Iā€™m going to post up my results shortly! Very interesting!

#5

One other thing I forgot to mention - although the fuel line nuts have notched shoulders, they are NOT reverse thread.

#6

Iā€™ve finally gotten the car back together - big difference!!

All engine lights are gone, and so is the lumpy cold idle. Lots more power.

I will be able to post up the cleaning process soon enough - please stay tuned.

#7

Thatā€™s awesome. Good to hear. I would like to hear more.

#8

Yeah, thatā€™s amazing Paul! Great news!

#9

Beautiful write up! Well Illustrated thank you!

#10

I did the carbon clean today, and threw in a JHM intake manifold spacer.
Now I have a tick coming from the car. Itā€™s really pissing me off.
I didnā€™t break off any tie wraps while cleaning the valves, and I didnā€™t drop anything in the engine.
WTF Iā€™m lostā€¦

I also changed out spark plugs.

Any ideasā€¦ I know its hard since you guys canā€™t hear it.

Russell

#11

welcome to the site russ.

You should be ok. The spacers are a good add on. You will be very happy they help a lot

as for the tick is it rpm dependent. how loud is it where is it coming from exactly

#12

It is RPM dependant.
One of my friends said it might be how it usualy sounds with all the gunk gone, but that sounds like horse crap.
It sounds like a tick, that is to loud to be coming from a luxury car.
Iā€™ll try to get someone else to hear it tomorrow.

#13

Feel free to use us. If you can grab a quick video on your phone and post it up. Chances are it is just the FSI system. Its loud. And like you said now with the gunk gone it has less stuff to muffle the injector clack as its called.

#14

I will try to catch a video.
Here are my possible. Haha
One this thing is annoyingly loud when clean, which would be dumb.
Two with the spacers installed the fuel lines are actually touching the intake manifold. Should I go in there and try to move them away so they arenā€™t in contact.
Three I forgot to put the 2 T30 screws back in on the fuel line brackets that go across the top of the manifold and under the throttle body plenum at the back to the drivers side. I will take the intake Y plenum off and put those back in.
This made me a little angry last night after working 8 hours on the car.

Lastly
JHM sent me two passenger side gaskets, had to get a buddy to go to the local stealership to pick up a new one. And then later I realized they didnā€™t send the longer bolts for the spacers. Had to get same buddy to drive me to Home depot to get twelve M6x60 to tighten the intake manifold down.

#15

Do you guys think the possibility of after a carbon clean a little carbon going into the cylinder could do damage.
One of the valves I was working on was so caked I sprayed the cleaner in there thinking the valve was shut but it was actually open enough for some carbon to fall into into the cylinder.

I sucked everything out that I could with a Vacuum. But the valve was only one about 2 or 3 MM.

#16

After looking into more and running Vagcom . itā€™s the intake manifold.
Bank 2 stuck closed.
Since there are 5 plugs in front of the manifold. What is the chance I plugged in two if them to the wrong sensor.
Or maybe I banged it around putting it back in and jacked one of the solenoids up.

Does anyone know how to put our S6 in service mode to give me some more room to poke around up there.

#17

I found this diagram to say what everything is.
I would dernif I switched the wires for #2 and #5

http://workshop-manuals.com/audi/s6_quattro_sedan/v10-5.2l_(bxa)/engine_cooling_and_exhaust/engine/intake_manifold/component_information/service_and_repair/intake_manifold_assembly_overview/page_4813/

#18

Russ

I would suggest starting a new thread just for this issue if you can post the code that would help us see what your gettting; If you hooked up a wire wrong you would be getting a code for it.

Also if you can take a picture of the front wires. We will be able to look and see if they are wrong. You can load pictures directly to your account on the site. Just click the upper right hand part of the page that says upload.

#19

Whereā€™s the part two? \im wondering how to actual clean off all the carbon. Is the build up in the manifold section you remove or on the valves and ports on the engine block?

#20

The carbon is on the valves in the cylinder heads. There should be more updates in the next few weeks.