[MrSeabass]

Edit: very likely not broken again, just some leftover residue made it to the coolant tank. Leaving original post up just in case.

... I don't think it's fixed.

Drove it for probably an hour or two, and there's oil in the reservoir again. Checking engine oil level shows it's 1/3 down from full. I don't see/smell oil anywhere, and the engine still appears to run fine.

Help

[Wgosma]

Borrow a combustion gas detector from an auto parts store and check to see if there are combustion gases in the coolant; simple, easy and quick.

Pull a couple of spark plugs - if you detected excessive oil coating and/or coolant on the plugs - that's a head gasket breach.

Good luck/Bill

[MrSeabass]

Ok might be a false alarm as I did not account for oil that is fully in the engine block, plus residual oil in the coolant.

I'll pull a plug, but right now it's been idling for about an hour with no change in either level now...

[Wgosma]

Checking for the presence of combustion gases in the coolant is Gold standard for head gasket testing. Any auto parts store will loan you tester, you buy test fluid, costs < 10 bucks. Quick and simple to test.

[MrSeabass]

Yeah 92.63% sure it was a false alarm; took a massive gamble after pulling three plugs and seeing nothing by driving in both stop-and-go and also high speed highway driving for the past hour. Oil level didn't change at all, and seeing how rapidly the oil was drained last weekend, it had to have been the OFHG with whatever oil in the reservoir being what I didn't get cleared out.

I'll do some close laps near my house later tonight to be sure, but regardless I'll skim and flush the coolant again.

[MSport_Jon]

Originally Posted by MrSeabass

Yeah 92.63% sure it was a false alarm; took a massive gamble after pulling three plugs and seeing nothing by driving in both stop-and-go and also high speed highway driving for the past hour. Oil level didn't change at all, and seeing how rapidly the oil was drained last weekend, it had to have been the OFHG with whatever oil in the reservoir being what I didn't get cleared out.

I'll do some close laps near my house later tonight to be sure, but regardless I'll skim and flush the coolant again.

What you are describing is normal. There will be oil in there for some time. Flushes regularly will get you there.

[MrSeabass]

Sorry, never posted a followup. Coolant has been thoroughly flushed again and car runs like new, so problem solved.

[Dekero]

You will be forever and still not get all the oil out without adding water mixed with a hard degreaser like Purple power, to help emulsify the oil into the water and dump from lowest hose... Helps to run the system up to hot, cool some, drain....repeat.

Once it's coming out clean(Mine took a total of about 15 flush cycles) flush once more with distilled.... And dump and refill with coolant..

And use tap water for those short flush cycles.... Don't waste money on all that distilled until the final flush.