Hi All,

I have a 2001 Audi A4 1.8T. Check Engine light is on saying that the Cat is not running to full potential. It has been fine the last couple weeks then the other day I started the car and the coolant light came on. I checked the coolant and it was a light coffee color. I tried driving it to my friends house so we could flush the coolant out and add fresh coolant, and we didn't get but 5 mins down the road and the car was overheating. We stopped added more coolant and by the time we got where we were going it had pretty much boiled over. We flushed the coolant out and like I said it came out like a light coffee color, but it was very thick. And had alot of Oil in it. It was in the overflow tank, radiator, and one side of the oil cooler. The other side had fine coolant in it. We drained the oil and it did not look to have coolant or anything in it, but we were loosing oil somewhere.. Not sure if it is all going in the coolant, because you can defiantly smell and oil burning smell after you drive the car. (Turbo?) Did a pressure check on the oil cooler and it seems to be working. After all that was completed the Oil light came on the way home and it overheated again. Added more coolant and it seemed to come back down and ran at normal temp the entire way home. Sorry for the long post... Does anyone have any ideas as what this could be?

 

Sounds like a head gasket. blowing oil and exhaust gas into the collant causing thick coolant sludge and overheating.

 

the only thing that would cause this would be a cracked head gasket.

 

What other symptoms should I be seeing if the head gasket is cracked or blown? I have had the car for a few months and it has been driving fine and then all of a sudden this happened?? Does something like this happen that quickly? The car is actually running fine..no loud noises coming from the motor or what not. No smoke coming out the exhaust. Could any of this be caused by a blown turbo? does the turbo have both coolant and oil going into it?

 

depending on where it cracks and severity determines what goes where for the head gasket. sometimes you get coolant that escapes to the exhaust and smoke, sometimes you get exhaust and oil escaping to the coolant. As the crack grows it will cause more problems.

I would get it to a decent indy mechanic and have it checked out. One more good overheat situation and you might be changing the whole motor when the crankcase fills with coolant and you spin a bearing.

Head basket symptoms can be tricky sometimes but you have classic symptoms here with oil in coolant and overheating. I am by no means an audi expert so hopefully one of the moderators will chime in and suggest some other things to check.

I have seen other posts that blamed the oil coolers for the oil in the coolant, but that didn't include overheating like you described, just dirty sludge coolant. Your overheating would imply exhaust gases getting in to the coolant system and that only happens with head gasket failure.

Get it somewhere before 'car is running fine' comment turns in to 'car WAS running fine'.

 

that causes cross-contamination, oil goes to coolant & coolant goes to motor oil side ... it's classic symptom of showing sign of motor oil in the coolant system, muddy brown color. I bet your motor is burning coolant as well and will smell the coolant's sweet smell at the exhaust. You should also see air bubble coming up in the coolant (overflow tank) because motor's exhuast gas is present in the coolant.

That's why your cat reports problem because the burning of coolant through it will hurt the cat efficiency... it also explains why you get overheating.

Head gasket has to be changed ... this is very popular in older Subaru. Older model has internal leaking, and newer model has external leaking. 'Bars' coolant conditioner will help on this condition. It is for prevention and I wonder it will help now.

http://www.amazon.com/Bars-Leaks-Gas...8130873&sr=1-2

http://www.amazon.com/Bars-Leaks-110...=cm_cr_pr_pb_i

It is a $1200 job in Subaru Outback and Audi should cost more than that I think.

 

blowing oil and exhaust gas into the collant causing thick coolant sludge and overheating

 

Blown head gasket or cracked head.

 

It is NOT a BLOWN HEAD GASKET. Your OIL COOLER IS BAD. Same thing happend to my Audi. I was driving home when it was overheating. Opened up a coolant tank and there was oil in it. Next day bought a brand new oil cooler which cost me $60 and its located under the oil filter, replaced it now runs like **** lol. Make sure to flush your system and get all of the air out and replace cooling temp sensor.

 

Hey folks please help, problem is oil in a coolant and very thik oil in a coolant, i replaced the head gasket, and its still doing the same thing, Crap(( other things want to add that, when you open the cap where you put oil the exhaust smoke is coming from there, and also top radiator hose is getting to much pressure. please if anyone knows what to do and whats the problem please email me jeffindiana@usa.com