Oil in coolant, A3 32 V6

[catso]

A3, 3.2L V6, 90,000 - miles runs fine but since a couple of days ago intermittently shows the low coolant warning.

Checked the coolant level which is not low but coolant is a nasty looking brown emulsion. Can only assume the coolant level sensor (2 probes rather than a float) is showing an error due to different conductivity of the liquid?

Anyway oil appears to be nice & clean with no emulsion in it, similarly oil filler cap has no residue and oil level is still OK (car has never required oil top-up between services).

It appears that oil has contaminated the coolant and I'm thinking the likely cause would be head gasket? However before going down that route I'm wondering if anyone might know of any other likely or common cause? Oil cooler etc.

As said above car runs fine, no noticeable loss of power or fluids, idles smoothly and runs at the correct temperature etc.

I am planning on changing the car soon but would have liked it to be trouble-free until then and actually worth something come change time.

I'm thinking radiator sealants (K-seal) etc. only work with coolant to oil leaks rather than oil to coolant due to the pressure/flow thing?

Any ideas?

[catso]

xjay1337 said:

Oil cooler.

Don't use any of the rad weld type products.
horrible nasty things.


9/10 if the cooler has gone you only get oil in the water and not water in the oil
About £120 for the part. Easy fit.

Now that's better news than I was expecting, any advice on determining that this is the cause?

[catso]

OK, thanks.

I had a quick google for the cooler and found this; http://www.ebay.co.uk/itm/201101361558?_trksid=p20... which says 'Oil Cooler - Gearbox', is this the one or is there a separate engine oil cooler?

If it makes any difference the car has the DSG gearbox.

[catso]

OK, I see now that it's a heat exchanger type cooler so uses the coolant to cool/warm the oil, whereas the gearbox cooler is an air cooled rad, presumably to cool the DSG box oil?

I would like to confirm that it's not the head gasket before fitting the cooler but it would certainly seem the likely fault given the symptoms.

It does indeed look cramped in the front so getting at it maybe tricky, I might decide to get this done by a professional.

[catso]

I called in at a local friendly garage this afternoon, they tested the head gasket which they say is fine. They also agree the cooler is leaking and having looked at it with them I've decided I don't have the inclination to do it myself, so I'm getting them to do it next week.

Thanks for the advice.