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oil burn at idle
Posted: Sun Sep 09, 2012 10:07 pm
by ns_wrestler130
I have a 90 si with a b21a1 with about 180 thousand it. The head was just rebuilt as the car had a bad valve when I got it. Now its burning oil, quite a bit of smoke after it warms up and is idling, smoke clears up while driving, and starts again if I sit and idle or the car sits for a short period of time. A compression test was done with the rebuilt head and everything looked good. The cylinder walls looked good. I don't know if this would be caused by the rings since it isn't doing it all the time. Any ideas would be greatly appreciated, thank you.
Re: oil burn at idle
Posted: Mon Sep 10, 2012 12:14 am
by spiffyguido
Wow. That's quite a problem.
I have to ask one question. Is it possible that the smoke is just less visible above idle because it is being ejected faster or you're moving? More smoke at idle seems odd to me and I can't quite think what might cause that.
You said that you just rebuilt the head. Was anything else changed at the same time?
Re: oil burn at idle
Posted: Mon Sep 10, 2012 1:36 am
by ns_wrestler130
There was no other change. And it actually stops smoking. The smoke is still visible when you first star driving, but clears up after a few minutes and does not start again until idling for several minutes. I'm at a loss for a cause.
Re: oil burn at idle
Posted: Mon Sep 10, 2012 10:04 am
by spiffyguido
And you're certain that this is oil smoke and not steam from water leaking into the cylinders?
Re: oil burn at idle
Posted: Mon Sep 10, 2012 11:00 am
by ns_wrestler130
It is very lightly colored but doesn'T have that sweet smell. I'm monitoring oil and coolant now to verify. Are you thinking maybe the new head gasket is leaking?
Re: oil burn at idle
Posted: Mon Sep 10, 2012 11:17 am
by spiffyguido
Yeah, that's what I'm wondering. It still doesn't explain the difference based on RPM, but quite often the steam is most visible when the exhaust speeds are low. Maybe when the engine is cold, crack open your radiator cap and see if there's any oil floating around in your coolant.
Re: oil burn at idle
Posted: Mon Sep 10, 2012 11:20 am
by ns_wrestler130
I'll go check my car at lunch and post back in an hour or so
Re: oil burn at idle
Posted: Mon Sep 10, 2012 12:37 pm
by ns_wrestler130
No oil in the radiator and no coolant in the oil, but I am down about a quart of oil so I'm sure it is pull that is burning. I think the rings were already worn and are gummed up from sitting so long is just making it worse
Re: oil burn at idle
Posted: Mon Sep 10, 2012 6:35 pm
by spiffyguido
Yeah, the rings are the next most likely source of the problem. Might be worth taking a look at them.