01 S80 2.9 - Oil in coolant tank! Topic is solved

villagepc · Post by **villagepc** » 30 Apr 2018, 11:01

Ever have a car deal you "just cant pass up". I'm a glutton for punishment.

2001 S80 2.9, 149k miles. Clean carfax.

No check engine lights, no warning messages, no smoke from exhaust, no idle issues, no trans issues (shift / flares) - absolutely no outward evidence that there is anything mechanically wrong with the car.

Car was driven on a frenzied 1 hour trip down the freeway at 80 mph with zero issues as well. No overheating, smoke, or codes showing up.

Open up the coolant tank, theres a bit of frothy brown goodness in there. sadface.jpg Engine dippity stick / top of motor shows no signs of coolant (brown frothy smeg).

I'm ordering a new oil cooler (kit) and will start from there. From what I've seen thus far on the intertubes - could be the oil cooler, or the head gasket. I'll run a compression test just for grins.

I'll keep ya'll posted.

Post by **regent** » 30 Apr 2018, 11:29

I would think, if it were the oil cooler's fault, you would be losing coolant into the oil when hot (because of pressure in the cooling system)

villagepc · Post by **villagepc** » 30 Apr 2018, 11:40

That crossed my mind too - I know on my V70, the oil coolant lines to the radiator are super high pressure (60psi?? or something) - I'm not sure if there is that type of oil pressure in the s80 cooler? I fully expected to pull the dipstick and see froth - or see froth at the oil cap - but it looks just fine.
I mean, logic would dictate if there's some sort of pinhole where fluids can swap - that the contamination would go both ways during the engines duty cycle from cold to hot - also assuming that the pressures are the same.

I'm kinda workin on the assumption that the oil pressure inside the cooler is higher than the coolant pressure - kinda like when the internal oil coolers tubes go bad inside radiators?

villagepc · Post by **villagepc** » 16 May 2018, 11:37

Picked up the oil cooler and swapped it out. Its a pretty straight forward job. Drain coolant / oil etc, a few choice words and some wrenching and voila.

I had more of a hassle cleaning out the residual oil from the cooling system versus swapping out the cooler. Used some non-foaming dish detergent and ran it through a buncha times.. then cleaned up after with some DI water. Burped the system once and its been peachy keen since.

Its been a week of using the car, and there's no trace of oil in the coolant now.
And without having a jig to test the old one out, there no real way for me to be 100 percent sure that was the cause. Perhaps someone poured oil in the reservoir tank? Who knows.