Coolant contamination

[Carbuff]

I did a really stupid thing:

I removed my intake manifold without adequately draining the coolant. Got about 3 oz of coolant in each cylinder.

I've finished my repairs, and have turned the engine over by hand to allow the coolant to drain into the sump (verified by my borescope in the sparkplug holes). I have not yet run the engine.


My question is, is my oil ruined by the coolant? (It's Prestone 'All Makes - All Models" if that makes a difference.) It's only 400 miles old, Mobil 1.

I'll be draining the sump as I wait for a reply.

 

[SirTanon]

Well...

Not knowing what car this is for, I'm just going to guess here and say it holds about 5 quarts of oil, and has 4 cylinders, since that's basically what my daily driver has.

Based on this, we can say you got approximately 12 ounces of coolant mixed in with 160 ounces of oil.. or about 7% of the total combined volume.

Unless you can RELIABLE extract/separate nearly ALL of that coolant from the oil, then there's NO WAY I would use the oil.. and even if I was able to get all the obvious coolant out of the oil, there's still bound to be a bunch in there you can't see.

Personally, I wouldn't want to run it... but if it has not yet mixed, and you can get almost all of it out, then I suppose you COULD technically use it.. you'd really want to get it up to operating temp and run it for a while to boil off the water, if you did. Run that for about 100 miles or so at operating temp, and then drain it and refill.

If it's at all mixed, then put fresh dino oil in there, and run it for a REALLY short OCI.

 

[CT8]

Do a couple oil changes just because.

 

[Carbuff]

I don't see why it matters, but it's a 1980's turbo 4 cylinder. Total oil system capacity is ~7qts but it is mid-engine and has an oil cooler up front.

Drained about 5.2 qts of liquid out of it, into my calibrated bucket. Looks as if the coolant mixed with the oil...nothing that I can skim off.

Guess I could use the oil in the lawnmowers come spring?

Since I didn't run the engine, and everything ran into the sump which is drained, I'm saying that putting new oil in the engine NOW will eliminate any harmful amounts of coolant. Nothing was pumped into the engine.

 

[Carbuff]

Update: 5 quarts went back in to bring it up to where it was before on the dipstick. (I had checked)

 

[Ducked]

I too did a stupid thing. I got rainwater in my engine (cloudburst while the rocker cover was off and I was fetching something) and didn't get it out quick enough. Wrecked it.

Coolant is probably not nearly as bad as Taiwan rain water but once-bitten I'd be wanting to get the fresh oil good and hot asap to limit the probability of corrosion.

 

[SilverC6]

Dispose of the coolant contaminated oil.

Change the oil a couple times as recommended above.

Use a short OCI for next time too.