Coolant questions

[MikeCT]

Inside the expansion tank on my car it looks as if there is oil mixed in with the coolant. The oil isn't milkshake; at least not on the dipstick. I'm wondering if:

1. It is oil in the coolant but no coolant in the oil what is a possible cause.
2. It is possible that if the cooling system was filled with the wrong type of anti-freeze that it would cause the hoses to breakdown leading to junk in the cooling system.
3. What is more likely?

I am planning on flushing the cooling system so I will have more info about the coolant (if there is anything in it, I might just be worried for no reason)

[CJFusco]

Mike should add that it is not perfectly clear if it is oil in the coolant tank. It looks like a couple drops of oil are congealing on the surface of the coolant... not a whole lot, but enough to raise an eyebrow.

[MrPants]

oil in the coolant is a sign of bad oil cooler seals.
1. i have not gotten a good answer to this either. todwic suggested that the oil sytem is perhaps under higher pressure than the cooling system. maybe when the seals just start to go oil shows up in the coolant before coolant shows up in the oil
2. wrong types of coolant are bad for the engine but i have not ever heard of them breaking down hoses (doesnt mean that it cant, i just dont know of that happening). hoses age and can break down. if this was the case i think you would just be loosing coolant.

[924Sman]

Our Texas collegue is right on! Time for a new OPV in the one piece style and a set of oil cooler seals! Save yourself alignment hassels and get a 9215 Oil pressure relief valve guide. Guide is about 20 bucks and the seal kit is about 30 bucks. CLEAN and FLUSH the entire system till no oil is seen. Do a "roto rooter" job on all the hoses and coolant tank. Oil will damage hoses over time and cause the hoses to swell. Unless your coolant is not for aluminum I would say the coolant type is ok. I personally use Prestone Extended Life Anti freeze. Sman