phattony57

About a month ago, my 2001 S4 overheated on me (the hottest it ever got was 3/4 on the temp. gauge). The coolant in the system had turned into brown ‘jello’ or a very thick brownish sludge. The car has always (3 years now) had a slow coolant leak (I consistently put in about 2 quarts every month), so I thought that I had somehow mixed something with the G12 coolant that I have been adding to it. So, I flushed the cooling system and put in new coolant right away and started driving it again. A week went by with no problems whatsoever and I decided to check the coolant again to make sure that the level was correct. I found that it was brown again...not ‘jello’ this time, but definitely milky. So, I did another flush and added new coolant. Another week went by and at the end of the week, I got a low oil level warning inside the car (first time this has ever happened). So, I checked the dipstick which showed no oil on it. I added a quart (synthetic 5W-30, changed every 3000 miles) and it still didn’t show any oil on the dipstick. So, I drained the oil to find that it is kind of watery and slightly milky too.

Is there a common point of failure that I should look at? Could it simply be the valve cover gaskets, or is it more likely (my worst fear) a head gasket problem or a cracked/warped head/block? Is there another way for the coolant and oil to mix on the 2.7t...maybe the turbos or the oil cooler? I haven’t had a check engine light with any of this trouble, and the oil pressure/temperature have always been normal. There also haven’t been any fluids leaking on the ground with the exception of the coolant reservoir losing a little out of the pressure relief hose once in awhile.

Any help or advice that anyone can give will be greatly appreciated.

s4ddriverr

id say its your oil cooler, the thing that the oil filter screws onto.

phattony57

Well, I removed the oil cooler last night and cleaned it up a bit. There doesn't seem to be any damage to it or the seal that goes with it. I did a "pressure test" by blowing in one coolant port while tightly covering the other and could not get any air to escape from within the core of the cooler, so it appears to be ok.

I guess I'll move on to the head gaskets. I'll pull all six plugs tonight to see if one is unusually clean.

mosmoe (OPG)

did you use an air compressor to pressurize the coolant line?

r1de23

dude your engine has a blown headgasket... you have all the symptoms.... good luck.....

phattony57

I'm leaning more toward the head gaskets now too. I didn't get time to check the spark plugs (but then, I've never had any white smoke come from the exhaust or the engine, so it's not likely that coolant is getting into the combustion chamber). But I did submerse the oil cooler in water and pressure tested the coolant ports with no air (bubbles) coming from the core.

Is it even possible for the oil and water to mix at the turbos? If not, I think I've got it narrowed down and will be tackling the head gasket job soon.

complacentsee

I can take a look at my old K03s this weekend. I would think probably not.

r1de23

i believe it is only oil that leads to the turbo for lubrication... not coolant..

phattony57

Actually, the turbos are oil and water cooled...check out this writeup on the 2.7t engine.

http://allroadfaq.com/downloads/tech...ne_english.pdf

complacentsee, if you do get a chance to check out your old K03's to see if some kind of failure could cause oil and coolant to mix, that would help me a lot. I wasn't having any trouble making boost though, so I have my doubts as to that being the problem.

complacentsee

Can do, won't be able to until friday evening/saturday though if that is an issue.