Oil in Coolant (Not the usual)

[jon squires]

Hi all, hope someone can help.

This is an old problem but I really want to get it sorted as the oil is slowly melting my coolant hoses.

I have oil in my coolant, lots of it. It's black and floating in a layer 3 inches deep in my expansion tank, not the browny mayo type.

No sign of mayo deposits on the dipstick or on the underside of the filler cap.

The car runs fine...

I have had the head removed and crack tested and rebuilt. No problems there.

I have had the oil cooler replaced. No problem there.

Can anyone think how this oil is getting into the coolant system?

I will need to replace the coolant hoses soon as the oil is eating through them and they will soon burst. I want to find the problem before forking out for new hoses!

Any help gratefully received.

Jon

 

[jon squires]

Sorry.... The car....

It's a 54 plate A3 TDI 140 with a BKD engine code

Jon

 

[johal87]

I would have said oil cooler as this has just happened on my friends fiesta. With the same symptoms

Since changing the cooler, have you flushed the system?

Next step maybe gaskets..

 

[jon squires]

Yes, it was flushed very thoroughly after the crack test and rebuild and also after the oil cooler change.

 

[RobinA3]

You could have a small hairline crack in the block itself allowing oil to get into the coolant gallery.

 

[jon squires]

You could have a small hairline crack in the block itself allowing oil to get into the coolant gallery.

Robin,

That doesn't sound good at all, I didn't think to have the block tested whilst it was apart. Do you know how you would go about crack testing the block?

I was hoping somone would tell me of some seal somewhere that might have perished and allow the oil into the coolant.

The only places I can think of where the oil and coolant can some into contact are the head/block and the cooler. Anyone know any differant?

Jon

 

[paddy]

Hmmmm, really intestine one this. The oil returns are mostly low pressure and i would imagine there would only be a couple of high pressure feeds up the block where the water jacket is. In 90% of places the water pressure would be much higher than the oil pressure so i would expect to see water in the oil, not oil in the water. Need to put my thinking cap on for a while...........

 

[paddy]

OK, i am pretty sure this is going to be a oil cooler problem. If its an auto the gearbox oil rad could be a problem but i suspect it will be the engine oil cooler rad wich has coolant lines to it. Only fix is an exchange rad really. HTH

 

[jon squires]

OK, i am pretty sure this is going to be a oil cooler problem. If its an auto the gearbox oil rad could be a problem but i suspect it will be the engine oil cooler rad wich has coolant lines to it. Only fix is an exchange rad really. HTH

Paddy,

Pretty sure the car doesn't have an oil cooler radiator, just has an oil cooler unit beneath the oil filter housing which I have already replaced. Tested the old one when I took it off and that was fine.

Jon

 

[paddy]

Sorry mate i mean cooler not rad, thinking in general as not up on the TD140. I know the oil cooler is a common problem on the Golf Tdi with your symptoms..I still would have expected water in the oil not oil in the water.