2008 E90 Oil in Coolant

Anyone ever get a little oil residue in the coolant reservoir?

Ups, never heard of but lets see what the tech guys says. Previous owner did oil top up a late Saturday night..?

Coolant should be blue

Has not been an issue I recall reading about in my 7 years here, but I agree it does look like you have oil in your coolant. I don’t know the most likely culprit. The OP mentions the oil filter housing gasket. I have not studied it and am not sure whether coolant passes through it.

Pulled the oil cap, no milky looking coolant mixing under there. Pulled the oil filter, looks normal. From what I can tell in the diagrams it looks like the coolant flows through the oil filter housing.

rmtdewz wrote

Just purchased a 2008 E90 M3 with 41,000 miles. After checking it over noticed oil residue in the coolant tank. Coolant looks very oily and after dipping my finger in it does have quite a bit of oil in it. Anyone seen this as a common thing with these cars?

My first thought is oil filter housing gasket..

Oil in coolant is one of the symptoms from a *Blown Head Gasket* !
Someone pulled high rpm's while your S65 was still cold...

#reallysucks !

I've seen this before and it might be no big deal. Put a shop towel in there and soak up the goo. Do that several days in a row and see if the amount on the rag is the same.

You could always do a coolant flush and see if the oil comes out. Sometimes there's oil in there during assembly, but I'd have expected your car to have had several coolant changes by now (every 2 years it should be done iirc).

I don’t think factory spec coolant changes are 2 years. Probably 100k miles.

pbonsalb wrote

I don’t think factory spec coolant changes are 2 years. Probably 100k miles.

I agree . I have 54K km on it , and I never had a coolant change .
Oil in coolant is always a bad sign , like I said above ...It's the symptom of a *Blown Head Gasket*
I wouldn't drive my car like this , the chance of overheating and compression loss is big...
A lot of *white smoke* from the exhaust tips , and the smell from coolant can show what is going on..

Wow... only 41,000 miles and there's oil in your coolant expansion tank? That is horrible...

It could be a bad Oil Filter housing gasket -- that's where oil flows next to coolant and if gasket is bad they can mix....

and I think the reason why oil in the coolant and no coolant in oil is because oil runs at higher pressure ....?

Eh

If it’s just a gasket, that can be fixed. I am more concerned about why it happened since no one seems to suffer this problem.

pbonsalb wrote

I don’t think factory spec coolant changes are 2 years. Probably 100k miles.

Good point. I had my E46M3 thinking cap on.

I'd pull an oil sample and send to Blackstone. They'll let you know if you have water in the oil.

It's likely the oil filter housing gasket. It shows up as an issue when you google oil in coolant m3 or things like that.

I'd still try to soak up the oil in the coolant tank and see if it comes back. Someone may have put an additive in that has aged out and now looks like oil too. Unlikely a head gasket unless the motor has been severely overheated.

http://www.m3post.com/forums/showthread.php?t=1312849

I can’t see how the coolant is getting into the oil. The guy removed the water pump but I think that was for access.

Well

If it’s getting in from the engine, it may be a head gasket. Big job.

Hmm

It would make me think maybe the seller knew and sold the car to avoid problems.

Oil in your coolant like that is pretty game over. You will need to rebuild the engine, probably might as well do the bearings also, main and rods.

If I were you though, I would go straight to the dealer as they sold you a lemon.

Lemon laws in your state?

Any update op?