Smoke from oil filler cap

[masospaghetti]

I took my 92 EX on the highway for the first time today and it drove great, plenty of power, smooth to 80 mph. After I came to a stop I removed the oil filler cap. A far amount of smoke is coming out of the oil filler hole.

How much is "OK"? There's no indication of a blown head gasket (no milky stuff on the oil cap, oil on the dipstick looks fine). The motor has an unknown amount of miles on it. PCV valve has already been replaced. Compression test showed cylinders 2, 3, and 4 within a few psi of each other, cyl 1 was down just a bit (about 20 psi less).

This was the first time the motor got really "hot" since I bought it in November.

Thanks all.

[Raf99]

does it have enough oil in it?

If this is the first time it has been "hot" then it could be just burn off. I've seen this before but only when the car was low on oil.

[masospaghetti]

Plenty of oil in there. There's a fair amount of pressure coming out of the oil filler too.

PCV system should take care of crankcase pressure, yes? (assuming there isn't too much blowby)?

[93redcb7]

Plenty of oil in there. There's a fair amount of pressure coming out of the oil filler too.

PCV system should take care of crankcase pressure, yes? (assuming there isn't too much blowby)?

with the filler cap off there likely isnt even enough pressure to open the PCV valve. At least there shouldnt be.

[F22Chris]

I'm a bit confused. All cars will have oil smoke come from the oil filler after running. Oil coats the cylinder walls and gets burned. It's normal for some cars to burn up to one quart every 2000 miles.

Crankcase pressure enters through the PCV, and through the intake hose. There's that skinny hose connected to a metal line, then to the intake before the throttle body.

When you have burned oil smoke coming from your exhaust, that's when you have a problem.

Your car is fine, man.

[Raf99]

Ya i guess. I never see oil smoke but maybe it's because I wait 10min before checking my oil after the car is turned off. The times I can think of taking the cap off after the car is shut off i still don't see smoke. Maybe once in my life i seen this but it was low on oil, causing the engine to get hotter than usual.

[GhostAccord]

There will always be vapours in the engine/crankcase and cylinder head. The amount of vapour or smoke, can be different between all engines. Type of oil used, moisture, exhaust gases passing rings, engine overheating etc etc.....

Usually the vapour/smoke is sucked out of the block via the PCV system. The high vacuum created by a closed throttle at idle would usually eliminate these vapours if the PCV system is working properly. A clogged PCV valve or collapsed hose between the intake manifold and valve cover could cause a backup of vapour/smoke.

That 20 psi less in cylinder one could be the rings passing, therefore the reason for more than usual vapour/smoke in the crankcase.

Add a teaspoon of oil to the cylinders before doing the compression test and see if the pressure equals out on that No.1 cylinder.

[F22Chris]

20psi is a lot. Definitely do a wet test. I think it goes without saying, but your car will smoke a little after the wet test.