07 - S6 Coolant in oil - Complete Engine Teardown

A6 All/ S6 All
#1

Originally I was going to wait until this project was complete (and confirmed successful) before creating this thread, but then I figured it would not give as much of an opportunity for people to comment or ask questions along the way.

I have had my 07 S6 for about three years now and have thoroughly enjoyed driving it for most of that time. Currently there is about 250,000 km (155,000 miles) on the vehicle.

I had my share of the typical v10 issues (oil leaks, intake flap failures, broken electrical connectors and injector related misfires) and addressed them all accordingly. As far as mods go, I have the JHM: tune, catback exhaust, intake spacers and LW crank pulley.

I installed a lift in my garage this past summer with the intent of dropping the drivetrain next spring for the purpose of installing headers and resolving the oil leaks that cannot be addressed with the engine in the vehicle.

It was then decided that the engine drop plan needed to be fast tracked when I discovered what looked like “chocolate milkshake” residue under my oil filler cap one day a couple of months ago. The results of a sample sent to Blackstone confirmed my suspicion that there was coolant getting into the oil.

Once the oil results came back, I performed compression and leak down testing to give me an idea of the general health of the engine and if there was evidence of a head gasket failure.

Below is a summary of the numbers I obtained. The compression was quite reasonable across all cylinders. The numbers were still climbing when I stopped cranking but I wanted to limit it to six compression cycles on each cylinder for consistency. The leakdown numbers were ok with a couple of cylinders posting notably higher leakage rates than the others. At no point did I hear air coming out the intake, exhaust or adjacent cylinders so I was confident at this point that the leakage was mainly blowby past the rings into the crankcase. I will redo the leakdown test before I re-install the engine back in the car.

http://audirevolution.net/addons/albums/images/784397960.jpg

Other than the headgasket, the only other potential oil/coolant mixing points I could think of were the oil cooler and the internal coolant pipes that run from the cam timing covers into the ends of the cylinder heads.

At this point, I figured I would just pull the cam timing covers off and change the o-rings; then pull and pressure test the oil cooler and replace if necessary.

I am doing this work in a two car residential garage. It was obvious that with all of the tool and storage cabinets already in there, I would not have enough room to do any work on the dropped engine with the car in there as well. I needed a way of rolling the dropped engine/tranny combo out from under the car and then a method of rolling the car out of the garage without the subframe attached.

I ended up modifying a motorcycle lift by adding a sheet of plywood to stiffen up the deck and a set of four 6”casters that would contact the ground once the lift was fully lowered.

Here is a shot of the lift before the casters were added. It will make a good variable height work platform for the garage when this project is done. I would sell it but I very much doubt that this will be the last engine drop I ever do.

http://audirevolution.net/addons/albums/images/314978929.jpg

The mechanical part of the drop was very straightforward. I went pretty well by what is presented in the Bentley manual. I found removing all the electrical from under the cowling more cumbersome as you have to be very careful not to pull too hard on any of the wires as some of the connectors are getting quite fragile in their old age. When you are lowering the engine (or raising the car), the ecus and all of the other electrical has to be piled on top of the engine. In my case, I really had to watch the height as I can only lift the car so high in my garage and I still had to be able to roll the lowered drivetrain out from under it. It cleared by about 2”.

Here is a shot of the dropped engine being rolled out from under the car. You will notice that I have a winch line on it to keep it from getting away on me due to the slope in the floor of my garage.

http://audirevolution.net/addons/albums/images/695904436.jpg

To get the car out of the garage, I lowered the front end onto a dolly I made and pushed it out using a winch to stop it from getting away on me due to the slope of the driveway. I will also need it to pull the vehicle back in for the re-install.

Here is a shot of the dropped powertrain on the lift. You can see the front end of the car on the dolly in the background.

http://audirevolution.net/addons/albums/images/233996758.jpg

Another one taken from the rear. One of the many pics that I took during the disassembly process.

http://audirevolution.net/addons/albums/images/251061558.jpg

You will note that the rear cam covers have been removed and it is not real pretty inside

Here is a closeup:

http://audirevolution.net/addons/albums/images/935322962.jpg

This stuff is like tar. It does not come off easily with a simple wipe of a rag.

I am pretty sure this is the result of a major overheating (due to loss of coolant) incident that I had a couple of years ago. The engine got so hot that the red oil light actually came on. I had already been driving for about a half hour with the engine coolant temperature gauge pinned but it was a situation where I could not stop the car so I drove for another couple of minutes (with the oil light on) till I got to my destination and then shut it off. I thought for sure the engine was done. It was not a good situation as I was 200 miles from home in an underground parking garage with no tools. I went out the next morning to see if I could find the source of the coolant leak. I could not see anything given the limited visibility we have of the hoses under the hood. The oil level on the dipstick was good although it was a little on the dark side. I had to get the car out of the underground parking so it could be loaded onto a flatbed for the long drive home. I was quite relieved when only the coolant level warning came on and not the one for the oil when I started the engine. After getting it home, I found that the short right angled coolant hose that connects to the alternator had failed. Its premature failure was likely the result of me being a little too rough with it when I changed out my oil cooler o-rings about 4 weeks earlier

Here are a couple more pics showing the extent of the overheated oil situation

Under valve covers:

http://audirevolution.net/addons/albums/images/985950915.jpg

Oil pickup tube and pump inside upper oil pan:

http://audirevolution.net/addons/albums/images/913034827.jpg

After seeing all the “cooked” oil, I decided I was going to have to take it right down to the bare block to inspect and clean everything.

At this point, I am going to fast forward to the stage I am at right now as I am sure pictures of dirty parts in a partially disassembled engine are not going to be of interest to a lot of you.

I have the cylinder block separated from the crank guide plate with the crank removed right now.

http://audirevolution.net/addons/albums/images/57985435.jpg

I wanted to see the condition of the connecting rod and crank journals and bearings given the low oil pressure light that came on when I overheated the engine.

Here is a shot of the crank guide frame (engine bed plate) with the lower bearing shells still installed

http://audirevolution.net/addons/albums/images/920367062.jpg

As you can see, there is a fair amount of scoring in the bearing for journal number five and some to a lesser extent in the other five bearings. The crankshaft journals all look fine.

I did not take any pictures of the rod bearings. There was no scoring on them; just scuffing similar to what you see on the bearing for journal #1 above.

I have replacement upper and lower bearing shells for both the crank and rods on order along with all of the bolts. I will be verifying that the radial clearance for all of the bearings is within spec before torquing everything down.

That is it for disassembly.

The next step is always my favorite … cleaning. (stay tuned)

1 Like
#2

I am not worthy :o :o :o

Sorry about your troubles, but glad the car didn’t fail on you. Excited to see the overhaul process!

#3

Wow :o i’m with fenixgoon i’m not worthy.

This is awesome and insightful because i have dark dirty oil (don’t think i’m the only one) and i suspect i have coolant mixed in somewhere. But dreading the idea and cost of dropping the engine and opening that can or worms.

Do you have a youtube page? this would be a great DIY video series for the tear down and the build of the motor.

#4

eng92 GREAT POST…EXCITED AND FOLLOWING ALONG. Excited to see how this comes along. Very helpful for the entire platform.

#5

Send your oil to Blackstone for analysis to take the guesswork out.

#6

Thanks for the heads up on Blackstone, i requested a free kit and will send in after my next oil change.

#7

Phase 2 - Cleaning

Definitely the most tedious part of the process. This is one of the few instances where you would rather have a four banger.

I started with a number of different solvents including simple green, varsol, combustion chamber cleaner, brake cleaner and lacquer thinner. I wear gloves and an organic vapor mask when working with any of them.

The run-off is contained using PIG absorbent mats which are then dropped off at the local hazardous waste depot once saturated.

The brake cleaner is nice because it is a relatively strong solvent and the pressure from the spray helps to dislodge the larger chunks of buildup. I have gone through about fifteen cans so far cleaning the block, heads and the other large components.

Tooth brushes and other assorted scrubbers are used to remove the build-up that has been softened by the solvents. I do not use any metallic brushes (including brass) because they scratch the aluminum parts.

The lacquer thinner is probably the strongest solvent of the ones I use. It breaks down my 8mil nitrile gloves and I have to change them every half hour or so.

I was using it in a small glass container to clean the piston crowns and the ring grooves. The oil scraper rings have very small holes in them which were all plugged with burnt oil. Even after soaking them in lacquer thinner, it was a very laborious process to clean them with a tooth brush.

It was at this point that I decided to acquire an ultrasonic cleaner. After using it for a few days, I wonder why I did not invest in one years ago for cleaning parts. It probably is not any faster to clean things with, but it does a much more thorough job and there is no toxic odor in the air.

You do have to be careful with the heat setting and aluminum parts though as it will tend to darken them.

Here a few examples of before and after results

oil squirters

http://audirevolution.net/addons/albums/images/841531949.jpg

pistons

http://audirevolution.net/addons/albums/images/465781467.jpg


cam chains

http://audirevolution.net/addons/albums/images/411272691.jpg


valve springs

http://audirevolution.net/addons/albums/images/554017642.jpg

Here is a shot of a carboned up valve and one that has been in the US cleaner for about 40min. The valves are steel so I turned up the temperature on the cleaner otherwise there is no way the carbon would have come off. I still had to do some scraping with a plastic scraper to get some of the more stubborn deposits off. I will be lapping them all to the valve seats once I finish cleaning the heads.

http://audirevolution.net/addons/albums/images/340607061.jpg

Here is a good shot of the cleaned bed plate. You can clearly see the cast iron bearing housings that are cast right into the aluminum. Until I cleaned it, you really could not tell there were two different metals there. I was wondering why the damn thing was so heavy when I lifted it off the block.

http://audirevolution.net/addons/albums/images/526938213.jpg

This is the stage I am at right now. The block does not quite fit in the tank but at least it will contain all the solvent run-off. It is going to take a while to do this one as there are so many internal oil passages that I have to make sure are clear.

http://audirevolution.net/addons/albums/images/261262172.jpg

I hope to be done with the cleaning towards the end of this week. The next step will be checking the decks and heads for flatness and making sure the crank bearing radial clearances are within spec.

I will also post up a picture and a list of all the parts that were procured for this project in the next few days.

#8

awesome teardown and thanks for the pics.
I too had coolant in oil. 9% contamination accoridng to Blackstone. It were the orange O rings in the back of the head that seal the connecting tube to the cooling passage in the head. hard, dry, brittle. Disintegrated when i picked at them.
Not a bad oil cooler, you would have oil in your coolant reservoir. Can build yourself a little leakdown rig to have peave of mind like I did with the cooler.
Cooler will have far higher oil pressure in it than coolant.
Good job and keep posting.
PS that hydraulic table is TITS! I wanted one when I did mine but didnt want to spend the 600 minumum i was seeing them for.

#9

This is a next-level thread. Amazing.

Greg5OH: have pics or a p/n of the o-rings you’re talking about? Assume this is an engine out job?

#10

Yes it is engine out. no way to pull the rear covers off in vehicle, too tight against the firewall.
You could attempt it in frame, but anticipate pulling the engine…

i dont have a PN on hand as i ordered so many seals at once, but can see what Im talking about in my video:
0:44 is the rear timing cover, O ring is inside of that.
https://www.youtube.com/watch?v=ahNtlkNAXhE&t=3s

#11

items 23 & 24 below

http://audirevolution.net/addons/albums/images/35294463.jpg

#12

Mine were in a similar physical state but I could not identify a location where they had been compromised.

Good point. I really was not thinking of the differential pressure. I did a quick and dirty test on my oil cooler. I filled it full of solvent and plugged one of the coolant lines. I hooked up the other line to an air regulator set to 15 psi. It held pressure and there were no bubbles in the solvent.

It is a handy rig. The only downfall using it for dropping engines is that it is a parallelogram style lift so it translates horizontally as you drop it vertically. That is another reason why I had the winch line on it so I could inch it forward as I lowered it to stop the engine from hitting the firewall. A scissor style lift would move straight down but would have a much higher lowered height and would cost a lot more.

#13

ah good to know that it has the horizontal translation. I don’t like that but the winch line is a clever trick haha. I made a fixed table as high as possible while still being able to lift my hoist up over it. 10 ft ceiling height so I was doing a little bit of squatting under the car.
Nice scissor lift with extension cradle on it so I can work standing up (or at least sittring in a roller chain is how I usually work) would be very nice.

#14

I have access to buy a set of all 10 pistons/rods(used of course) for about $100 or so. If you want, just let me know. dtspilot@gmail.com

#15

The VAG unit is pretty slick with the two separate sliding halves on the top so you can easily separate the engine and tranny.

I had to leave the tranny supported on the lift and then sling the engine from the crane while I took the bolts out. It was a bit of a struggle as when you are lifting the engine, you have no idea how evenly you are supporting it until it lets go from the transmission.

It should go back together easier as I can use the two straps to get the engine at the correct angle and then use the bolts to pull it and the tranny back together after the shaft and the pins are aligned.

#16

Thanks for the lead. What is the mileage? Are they out of an engine that suffered external damage so it could not be sold as a running unit?

#17

There was not much progress this week.

The rotating postal strikes up here have delayed the arrival of some of the things I need to move forward by a few days.

Here are pretty well all of the parts I have received so far.

http://audirevolution.net/addons/albums/images/331765063.jpg

There are a few items there that do not have to be replaced when overhauling the engine.
I am just replacing them because it is so much easier to do with the engine out.

The small flex sections in both of my y-pipes had rotted out so I decided to replace those. The right side can be done with the engine in the car. The left side cannot.

I am also replacing all eight O2 sensors because they are not that expensive and I believe 6 of the 8 require an engine drop to replace anyways.

Here is a list of everything with p/ns and descriptions. There are 85 different parts which, with the multiple quantities required for some parts, combine for a total of 400 parts.

I apologize for the size of the text. From what I can tell, this forum does not allow either the height or width of an image to be greater than 2000 pixels. I will reformat it into two columns in a later post.

http://audirevolution.net/addons/albums/images/838335127.jpg

#18

Extremely impressed man.

#19

Those flex sections can be done in car, did them a few weeks ago on a guys. It was very difficult to do the driver side.
And only if you are ok with MIG weld, and not stainless TIG.
It also helps if you have a 120 or 90 degree mig gun, the regular 45 is very difficult to get up at the top. My weld was probably the ugliest thing I have ever laid on top of the driver side…not happy with it…
What helped was dropping that steel cross member out of the way and pulling the O2 sensor.
Veracious Motorsports were the only ones I found that carry 1.5"x4" full stainless joints.
But its nice you just got brand new pipes. Get another 10 years or so out of them.

#20

Great thread, and good to see another fellow Canadian (I’m in Manitoba)

I’ll be pulling the engine at some point this winter and doing much the same, even if it hasn’t failed on my car yet.

I’ll make sure to take pics as I’ll be doing this without a lift. We did an engine removal at a friend’s garage on a 2013 M5 and we just took the front end off (which I’ll do) and swung the A/C condenser out of the way and jacked the car up and away from the engine sitting on a furniture dolly. Worked pretty good.