Chocolate Frothy Milkshake Like Substance in the Coolant Overflow Tank.... Um, WTF?

[nzhorsey]

Thick Brown Milkshake in Coolant Overflow Tank, ARRRRGGHH!
Hey guys

Love to know if anyone else has experienced this. I have just picked up a 2003 a4 Convertible 1.8t and I absolutely love driving it this summer.

I have just recently discovered that there is a thick brown milkshake looking substance in the coolant overflow tank. There is no milky residue under the oil cap, no milky residue on the dipstick, it is not overheating, and is driving perfectly!

The brown milkshake doesn't smell oily but rather has a peculiar fruity smell????

Does ra anyone have a clue at what could be causing this?
I should add it has only done 117km, has been serviced religiously, and we'll taken care of! Not a drop of oil anywhere.

Took the radiator off and there is only water in the top of the radiator.

My mechanic thinks that some young punk has put ATF in the coolant tank about a year ago when the transmission had some work done to it.

Any thoughts or help please???

 

[Mike.M]

That is oil mixing into the coolant or setious rust/corrosion.

 

[Mike B]

Or maybe some smelly washer fluid

 

[D9n dk]

is it automatic or manual?

 

[BakPak]

Like Mike said, washer fluid additive. That's what I immediately thought when I read this earlier today. I would flush the system and refill first before panicking, do that and run it locally for a couple of days.

 

[tom2]

First post in aaagggesss as I've sold mine

I had a bex 1.8t with the exact same symptoms. Turned out to be the oil cooler, which is what the oil filter screws up against and has 2 coolant pipes attached. I changed mine myself and after bleeding the system a couple of times was fine.. Mine also had no water in the oil, only oil in the water, was told afterwards this is because the oil runs at a higher pressure than the water.

If it is that it's an easy and cheap fix. Remove oil, then filter, 30 or 32 mm nut holds oil cooler onto the same threaded tube that the oil filter screws onto (unless you have a very long reach socket you need a spanner). Drain coolant, I did mine by removing temp sensor from bottom of rad. Disconnect coolant pipes from cooler and replace it, reconnect pipes and refill oil and coolant.

Took me less than an hour and I'm no expert. But was quoted £400 plus vat by my local Audi specialist!!

 

[tom2]

If possible can you post a pic of what the coolant looks like