car sits for a while = white smoke coming out exhaust
 

My camaro sat for about two weeks, and when I started it a little white smoke started coming out the exhaust. I drove it down the street, and after giving it half throttle a small cloud of white smoke filled the street. I never had anything like this happen before. I have Mac headers and no cat if this helps. Thanks for any suggestions.

Possibly bad o2 sensors.

I should have added I just changed them a few months ago. I also thought when you have bad o2's the exhaust smells really bad. I couldn't smell much today. :confused:

if it's on startup, might be teh valve seals

sounds like valve seals. does it eventually go away after driving a little while only to return after sitting a while? this usually is caused by valve seals, but it could be something else. how many miles are on the car?

It did go away after letting the car warm up and driving it down the street. This is the longest I've ever gone (2 weeks) without starting it, and it's the first time I've ever noticed it. The car has 86k on it by the way. Is this a major problem?

sounds like your valve seals are bad. let it sit some more and try again. if it blows smoke again id venture to say its the valve seals. you could try valvoline high milage oil. supposedly it will help things like this. if your seals are gone youll have to tear into the heads.

also check your oil make sure there is no water in there. or did it start blowing smoke instantly upon start up?

id look into these things and then talk to a machine shop or a trusted mechanic. someone that can actually look at the car and here it run. its major in how much it costs and what it will lead to, but its not that bad. if its the valve seals your engines not going to grenade from this, but it will screw up your valves over time.

It started instantly. I think I'll switch to the high mileage oil....thanks for all the help everybody.

If your car sits for a while, condensation will build up in the exhaust and burn off for a few minutes when you start it.

mine gets so bad in my truck that it leaves puddles on the garage floor.

next time you do that, try getting a whiff of the exhaust to see if it smells acrid like oil burning, sweet like antifreeze, or just normal. could just be condensation like blk94 says.

GM has had a pretty bad rap on valve stem seals though. good luck.

Definatly sounds like the valve seat...after a bit of age/mileage they'll allow a small amount of oil to leak onto the top of the valves...at startup it burns off thus the white smoke that goes away.....'round here it's call the "chevy salute" cause they all do eventually. Unless it get bad even when the car sits overnight it really isn't even worth worring about unless your just real anal...and there nothing wrong with that....I look for excuses to tear my stuff apart :D

Black smoke= unburned fuel
Blue smoke= oil
White smoke=condensensation/water

thats true but the blue tint of the oil smoke may not be noticable. besides white smoke caused by water isnt smoke. its steam it disapates once it comes out the exhaust. smoke doesnt disapate it just floats away. steam wont fill a street with "smoke" either. just tryign to clarify since its confusing sometimes. Trey

I started it again today, and it smoked for a good 3-4 mins. Would steam from condensation last that long? There also were a few drops of water dripping from the exhaust pipe.

well i donno about this, but its just a thought comming thro my mind, is 50/50 antifreeze and water still steam or is it smoke?