Ok i have a 1996 Cougar and It over heats the check engien light comes on there is a few puffs of white smoke wile the car is on and it has engien coolent dripping off the exuast. The car shot

At IDLE the PCV does not open very much and therefore there may not be a vacuum under the valve cover.. maybe a couple psi. Try holding your hand over it and increase the idle? Does the air stop or reverse? (as you increase engine speed, the vac in the intake manifold increases and opens the PCV more so it will pull more gases out.) If so, I'm thinking you're OK. If your rings were really bad and you were getting lots of blow by you'd probably be seeing a Check Engine light (and other problems), and the air coming out would have smoke/oil vapor in it. No oil in the air cleaner? If 'no', then again, probably not excessive blowby. If I get a chance tomorrow, I'll check mine and get back to you how much is coming out of mine. Is it running OK otherwise?

If you have white smoke coming out of the exhaust after the car warms up then you have coolant getting into the cylinda white smoke after start up when the engine is cold is normal intill everything warms up

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white smoke mostly is caused by over fueling so what i suggest you do is first of all check if there is no leak on the injectors and if there is none which means your valve sterm seals are damaged.When the head gasket is blown out you may have problems like :-loosing power when driving,over heating,idling problems and oil mixing with water, its not your head gasket.

Have you replaced your O2 sensors? If no t i would start there. Other than that it sounds as though you may have a bad head gasket.

If the engine block has cracks or has worn it would be costly to replace (the block is most of the engine). Puffs of smoke would indicate a hole in a piston or severe damage to rings. You might have the engine checked out by a shop to see if it is salvageable. They would do compression checks and check for things like oil control problems. So it's repairable but likely expensive.

White smoke is usually indication of blown head gasket. That would explain miss also because plugs are getting wet from coolant. Have your cooling system pressure tested.

Its typical to see smoke on start up on older chevy engines due to worn valve seals. The oil seeps into the cylinder by following the valve stem after the engine is ran.

u have oil leaking on the exhaust system, have the car put on a rack and check for the source of leak.

white smoke is water
blue smoke is oil.
nest time try and smell the white smoke see if it smells sweet?
if it does its antifreeze.
and also black smoke is fuel (like a leaky injector )
hope this helps
paul

Welcome to FIXYA

There in only 1 thing i can think of where the white smoke is from it could be anitfreeze if so it would mean a cracked head or a bad head gasket if it gets worse then you have a big problem but if you check the water level and it looks fine then you should be ok for a while

if it was black smoke or a real dark gray then it would be oil


i hope this helps you out have a good day