Engine smoking

[Hoodbj]

My engine occasionally smokes. All will be good, no smoking and then it'll just decide to cover the car behind me. I was charging my ac today in the shop and it did the same thing. Been idleing about 10 minutes with no smoke and then looked like a train. It is white smoke and smells like oil. I haven't noticed any low oil levels and it's not constant, after a couple of minutes of driving it usually quits and all is back to normal. What could be causing this? I'm not sure but it seems worse when the a/c is on but that could be in my head. If I can't fix it I might just start up a mosquito business and call it good. Any help is appreciated

 

[350runner]

Check you spark plugs and note which ones see covered in oil.

 

[mtnmankev]

White smoke usually indicates coolant.
Black smoke is fuel.
Blue smoke is oil.
ATF burning on a hot exhaust pipe after leaking past the front pump seal on a Ford is an off-white and is guaranteed to make the person tailgating you back way off.

 

[bucket]

I know that the general rule is that oil smoke is blue. But depending on the lighting, it often has a white appearance.

The 4.3 in my S10 would intermittently smoke like crazy, it ended up being just a defective PCV valve.

 

[Hoodbj]

Thanks fellas, I will check Pcv valve and plugs this afternoon. It acts like what your talking about Andy, if I drive it for an hour it may only smoke for 5 minutes but it smokes bad. I've had vehicles in the past that smoked but not intermittent.

 

[bucket]

Yeah out of all the stuff I've owned, it's the only one that ever did that. The PCV valve seemed fine, but I replaced it with a new GM valve and the problem went away completely.

 

[Hoodbj]

Maybe a dumb question but how did you diagnose the Pcv valve? I've never messed with one before

 

[bucket]

I don't remember exactly why I suspected it was the problem, but I probably asked the question on a message forum. A PCV valve is supposed to let a small amount of air flow in one direction, but not the other. So if it doesn't seal properly, replace it. If you shake it and it sounds kinda gunked up in there, I'd replace it too. A new one has a nice free rattle to it when you shake it. I've also had them vibrate and buzz when the engine is at idle, so I replace it with a new one.

My S10's valve passed all the tests, but the new one was only a few bucks so I gave it a shot. It just happened to fix the smoking issue. The defective valve was the original and had around 175K on it anyway.

 

[rich weyand]

PCV valves are like 4 bucks, and are supposed to be replaced every major tune-up.

All it is is a little tube with a weight in it that blocks the hole at the bottom. When the engine pulls vacuum high enough to lift the weight, it breathes. When you get on the throttle, it closes. You shake it in the up-and-down direction, and it should rattle a clean metallic (tinny) sound.

Just put a new one on there.