Lots of oil in the coolant!

Stuart Cloy

Registered User
Hey folks

Ive got an A4 1.8T B5 with 130,000 on the clock and shes now started throwing all the oil into the coolant. It doesnt take long to virtually empty the sump. Im guessing the head gasket is away but i've also been told the block could be cracked. Im just not sure where to go from here.



Registered User
the scrap yard for a new engine?

have you checked the oil cooler? they are notoriously crap and corrode around the 129k mile mark. could be a good place to start before you write of the engine.

do you also have water in the sump (check dipstick)
overcooked it recently?
leaky coolant system?
heads dont normally blow a gasket without an underlying reason. usually too much heat from no or low coolant or huge boost!
I doubt the block is cracked..
I have tortured 5 VAG engines with varying amounts of boost and revs, abused to within an inch of their lives and never cracked one.

Stuart Cloy

Registered User
Thanks for the advice guys, one thing to note about 600 miles before this happened I hit a badger at about 115. The ****** bent the radiator, and I dont know if thats related. I didnt cook her, I noticed the temp gauge was above normal so I stopped the motor and checked the coolant and found a brown sludge in it. How would I go about checking the oil cooler?

Theres no water in the sump, and Ive not gave her huge boost lol. The coolant system doesnt leak either.


Registered User
Oil cooler is at the bottom of the engine.... so if you hit a badger, thats prob the culprit.


"Stick a V8 in it!"
Staff member
VCDS Map User
The oil cooler sits between the oil filter and engine. Looks a bit like a square brick with some pipes sticking out.

I'd just replace it, and hope!


Registered User
if there is oil in the water you have a leak somewhere.
one of them cant be leaking without the other.

if your radiator took a knock it could be steaming slightly and loosing coolant. You mention it had brown sludge, but what was the level like?
sometimes not even noticeable but over several hundred miles your coolant goes down and the temp go up. doesnt have to be sky high to blow a head. I blew one in an audi 90 by not putting the cap on properly and it lost about 2/3 of the reservoir.

I would guess you have either lost some coolant and ****** the head or the oil cooler is fritzed.

cant see how a badger would get up high enough to smack the oil filter/cooler assembly.
Do you have an undertray on?

Stuart Cloy

Registered User
No, theres no tray underneath. It drinks oil like nothing on earth and the coolant level rises, getting thicker and more oil like


Registered User
I'd be checking the oil cooler first, as it's the cheapest and easiest to check

Ditto my old 1600 A4 was diagnosed with a HG failure, the work was done and within a couple of hours the oil water mixing was back. Turned out to be the oil cooler which was a fraction of the cost of a headgasket

It looked like chocolate milkshake lol

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Registered User
No, theres no tray underneath. It drinks oil like nothing on earth and the coolant level rises, getting thicker and more oil like

cooler is fritzed!
get a new one for peanuts, easy to change, just like changing an oil filter.
one thing, I would clean your coolant system thoroughly before you invest in some new coolant.

drop a spoonfull of persil or another washing powder in the resevoir WHEN WARM (dissolves immediately before it gets to the radiator) and then run for a while, drain at the bottom radiator to clear and flush out until water runs clean.

I would be tempted to run some diesel through your oil system as well to make sure you have no Mayonnaise in there either.

its cheaper than a head gasket job!


Registered User
Hi I was just reading reading this article as I have exactly the same problem, oil in the expansion tank, AJL engine. When I discovered it I replaced the head gasket along with other gaskets as a matter of course. I did this because I wanted a good look at the faces of the head and block for minute cracks but found none, the oil cooler is 2 years old so I didn't suspect it but now the problem is still there I guess I'll just have to replace it. Doing the head gasket was a waste of time because it has not fixed the fault however the head had never been removed that I could see and the car is now sitting at 222,000 miles so knowing the head is not warped or cracked is of some comfort. I'll order a new oil cooler tomorrow and fit it asap unless someone has another idea ?


Dont replace it, Upgrade it !!
Oil cooler is the main culprit on this subject

Make sure you flush out the full system too as you maybe chasing a fault thats been fixed but not fully rectified.

Is there coolant in the oil ?


Registered User
Hi, No Coolant in the oil of much significance anymore? An update on this situation is that I have now replaced the oil cooler and flushed through the system A.B.A.P, When I pulled the head a while back the job turned into a bit of a mare with bolts snaping and stuff and I new the flush out would take time, I Finished of with just removing the expansion bottle every weekend at work and cleaned it through with bleach and tins of liquid brake cleaner till spotless because as you know its where the last of the oil likes to build up . What's left now is a thin film of oil which I now suck out with a syringe. I Check both the engine oil and the coolant twice a week and things look to be stable, I found the receipt for the oil cooler I fitted 2 half years ago so I will be sending them an email, The system is full of g11 at the moment but g12 will go back in again before wintertime Touchwood Bradderz 1988 I think it is done. :racer: