Car is a 2002 996 Turbo with 76000 miles on the clock.

A while back I got a low coolant warning. Checked in the back and rightly enough the level was low. Refilled and checked the radiators. They looked pretty bad so I put two and two together and didn't think much more of it. Planned to replace them when I got the time. Then I noticed it sometimes smoked more than usual on startup and on two occations made a LOT of smoke. Left the car in the garage until I had time to inspect further and when I got around to it found a puddle of creamy oil behind the drivers side rear wheel. Not good...





Lifted the car and started dismantling stuff, and found a very wet air inlet hose to the left turbo:



Pulled off the hose and found oil, a lot more oil. With a creamy tint to it...







Went back up top and even found this stuff in the air filter box:





And a good amount in here:





There's only a few hoses connected here, and the pipe to the resirc-valves was clean which only leaves the breather pipe from the oil tank. I noticed that the oil level had gone UP which was another troubling sign. It now read above full.

Then for the final verdict a peek at the oil filter:





The coolant tank looks suprisingly clean:






So, coolant gets into the oil, intermixes, overflows the oil tank and dumps the oil into the air inlet through the oil tank breather pipe. Which leaves the question WHERE does it intermix? I've googled extensively and struggle to find any other 996 TT that has experienced the same. Many emails back and forth with a reputable 996TT tuner concluded with no chance of this being a headgasket.

The car has a moderate trim level, K16 billets, 3,5" intercoolers, upgraded F-pipe, upgraded valves, 5 bar FPR, and the relevant ECU mods. 1,2 bar pressure, nothing crazy, car has been running great.


I've got more time next weekend and the plan was to start ripping stuff apart. If it really can't be the headgasket I guess the next possible culprit is the oil cooler? Is it possible to reach by just lowering the engine as far as it will go while still in the car or is this an engine out kind of job?

And are there other places where coolant meets oil and can mix?

I've tried pressurizing the coolant tank, to 5 bar even. Pressure held like a champ, which makes it harder to know where to start looking. Or is there some valve somewhere which isn't open unless the car is running that prevents me from detecting where it leaks?

 

Sorry OP, you're in trouble here. The most likely cause is a blown head gasket from running higher boost. The second possibility is the heat exchanger under the intake manifold, but I've never heard of one failing. Either case you will have to remove the engine from your car. You are likely looking at a rebuild.

 

It could also be one of the o rings in a cylinder liner failing or a cracked head.

 

this is a complete teardown. even if theres no crank or piston damage the bearing s in the motor will be toast. time to start the rebuild list. better rods, better head studs, complete gasket and bearing kit, head polishing . looks like you already have turbos and now you can get the most out of them!

 

Man I'm so sorry! Too bad we don't have a "pay it forward" fund for all of us to help out when this happens! Keep us posted. Brock
This post discusses engine rebuilds. May help!
https://www.6speedonline.com/forums/...st-engine.html

 

Spent the last three days ripping everything apart and... Nothing. The oil cooler looks good, pressure tested while mounted to the distribution housing to 2 bar, no leaks. Ripped the heads off, everything looks very good. For a 15 year old performance car it looks amazing. Cylinders still honed, all gaskets looks fine, no cracks dents or other defects to be found anywhere. Got around two liters of coolant out of the tank and sump when draining the oil, so there's a lot of water getting into the oil and such a large defect should be easily visible but... no. Kinda hard replacing parts when no parts look faulty. Didn't split the crankcase, I'll have to to clean things up and possibly replace bearings, but there's no water channels down there anyway so that's not where the coolant gets into the oil.

I'm starting to believe ghosts are behind this, or aliens... wtf.

Might ship heads and oil cooler to get it properly pressure tested or even x-rayed. Last option is a crack somewhere internally out of eyesight. I fail to find anyone that's experienced the same, guess I'm just really really unlucky.. Damn.

 

run a machinists ruler over the heads and look for warpage

 

Was there oil in the vac lines above intake - 16 check valve etc. and the oil vent lines that come off of oil tank?

 

I'll try later, but how would warped heads allow water into the oil? Oil is high pressure, coolant low, so if anything I should have oil in my water, not water in my oil..


With around 2 liters of coolant in the oil, the tank overflowed so yes, there was oil EVERYWHERE. Didn't specifically examine the vacuum pipes, but can't remember any oil in them. Why?

Most of it overflowed into the pipe between the air filter/maf and the turbos. Since the left side turbos pipe is located lower than the other all the excess oil went down to the compressor on the left turbo.

Pics from teardown here: https://goo.gl/photos/519Rv2m6cS1njdTL9

 

Gotcha, I was wondering why the drivers side turbo inlet had so much oil.

 

Question out of ignorance but... were those turbos water cooled?

 

No. K16 billets, just oil, just like stock.

 

except when engine is hot and off... weird issue here...

 

Has to be a cracked head or sleeve. Coolant pressure may be enough to bleed into oil passages right? Especially if the oil volume increased due to coolant displacement?
The oil in the inlet pipe at airbox is probably residual from the turbo being full of oil and coolant. Add a compressor wheel to that mixture .
Is there any oil in passenger side turbo inlet? If not wouldn't that specify the drivers side bank is the culprit?
Weird deal.

 

How about the oil cooler casting which is the same for the oil filter, any internal cracks or pin hole ? Strange to think the pressure was holding when you pressurized the coolant tank ????