Oil in Coolant

[mesidia]

OK, so today I took the 04 XC70 in for an oil change, and I had about 1/3 cup of what appears to be motor oil in the overflow reservoir (no coolant in the block). The car has 101K miles and it's well kept. I had it flushed 2X, and I figure after reading the posts here and other forums that these are the possibilities.

1. After servicing in desperation at Sears, the tech put power steering fluid in the coolant overflow, but just a little.
2. The Oil cooler coil in the radiator is leaking into the rest of the radiator.

I'm thinking it's 2, but the servicer this time said I'll know by the next oil change, and not to sweat it right now. Does anyone think the coolant could get into the block if it is #2? It seems like there's more oil pressure than coolant pressure?

[sjonnie]

Used motor oil is brown-black, used transmission oil is (hopefully) reddish-brown (check the dipstick). The correct power-steering oil is green, compare with what's in the reservoir. You should be able to tell them apart.

If you're not sure take samples of the transmission oil and engine oil and send them away for oil analysis. You may not be able to see coolant in the oil but if there is a leak you will be getting some for sure and the oil analysis will pick it up. Not sure I'd want to wait until next oil change, esp if you've got a leaking head gasket or something worse.

[Chilled Man]

I woudl at least have someone pressure test the rad at a minimum and do a coolant flush

[mesidia]

The substance was defenitely brownish to dark brown, like chocolate They didn't do the pressure test, so I'll do that next. They said it wasn't a head gasket, but I'll do the analysis anyway. What kind of labs do this? I use to do Jet engine samples in the AF, but i wasn't aware of a commercial market for this, where do I look, or what kind of tech should I talk to?

The flush was done, but all the substance found was in the coolant overflow. Thanks jonnie and Chilled, I'll work on getting to the bottom of it.

[sjonnie]

Sounds like motor oil to me. I've used Blackstone labs in the past, they're reliable, relatively inexpensive and will test for ethylene glycol (and a bunch of other stuff) in your oil. I guess theoretically the other place you could have a problem is the oil cooler.

[lexefx]

+1 Blackstone Ft Wayne Indiana - they ROCK! I do oil analasys regularly with them.

Lex

[tapanitja]

Hi, had this last year. the Behr oilcooler, bottom back of oil pan, leaked oil into coolant, almost black cream found in coolant expansion box!
Dealer renewed oil cooler, flushed engine and radiator but left old thermostat in place = allways open leading to more problems later with D5 DPF regeneration.
expensive job.
br tapsa

[mesidia]

Hey all, just wanted to let you know that I took some of the advice and it worked out fine. After warming it up good, I checked all the fluid levels and all the fluids were good except the coolant, it was a milkshake.

I had driven the car from PDX OR to Bellingham WA, and the check engine light came on after I got there. I looked at the coolant overflow first, and it was coolant on the bottom, with a milkshake on top, very strange stuff.

I checked the levels again (hot) and there was no difference from the previous experiment. I called a for a AAA tow (60 miles) and got it to a trusted Volvo shop in Bellingham my family uses and they pressure checked and eliminated everything but the transmission cooler, it was leaking into the coolant from the radiator. Since I was far away from home, I decided to have them fix it. About 1K with OEM parts and some hoses and labor. I think I was lucky I did not damage the engine or trans, and I'm picking it up next week. BTW, I'm figuring the check engine light that came on was the coolant sensor being fried by the trans muck.

[dhayner]

...got it to a trusted Volvo shop in Bellingham my family uses ...

Was that Bruce Cox? He is a local indie that I think is very good.

[mesidia]

Ya, Bruce Cox, although they did a great job, I wish they had done the thermostat and coolant temp sensor, because they both appear to be bad, maybe the trans oil affected them, I talked to Mike this morning and he said that's possible, I'll do it this weekend. That happened while driving back to PDX, but they did a great job on the radiator and I was really impressed with their diagnostic skills, they made no assumptions, and tracked down the problem scientifically, I'll go there again as I have a timing belt and fluid service due in 4K, including the haldex.