White Smoke coming from the tail pipe...

[THATDONFC]

What could be causing this? When I'm in fourth gear at about 4200 rpm's and I start to slow down my car backfires(not the problem) then when I start back up again there is a huge cloud of white smoke in my rear view mirror. Why?

Thanks, chris.

[pkbinplano]

are you losing coolant ? Could be head gasket

[Mike Self]

manifold via a leaky M/C and brake booster. Is your brake fluid level going down with no apparent leaks?

If it's a blown head gasket and the white smoke's coolant, you can confirm by holding a paper towel or Kleenex in front of the tail pipe. If it comes away wet on a warm engine, it's most likely coolant.

cheers

mike

[Mars]

White smoke is usually caused by some sort of humidity coming into the exhaust system. It "could" be coolant leaking out from the head (hopefully not) but, it could also be any type of water or moisture being forced into the combustion chamber and being burned out the exhaust. Like maybe some drops of water hitting the manifold or something. But, like the others said, a cracked head or leaking head gasket could cause this.

If you suspect a bad head gasket/cracked head issue:

On the next cold start while the car is warming up take a moment and smell the exhaust coming out from the rear tailpipe. If it smells kind of sweet like AntiFreeze it is a sign of a cracked cylinder head or also a potential blown head gasket.

Also, remove the oil cap and look inside to see if there is any milky white stuff in there with the valves, etc. Check your oil dipstick for whitish milky stuff too.

The only time it is normal to have white smoke is really on startup when a car is blowing out any condensation in the exhaust system (cold). After a car is warmed up you should not have any white smoke on either acceleration, deceleration (overrun) or idle.

Mike's trick is a good one too.

[Guest Anonymous]

When I'm in fourth gear at about 4200 rpm's and I start to slow down my car backfires(not the problem) then when I start back up again there is a huge cloud of white smoke in my rear view mirror.

Maybe I do not know how to interpret your question, but it sounds "loaded" to me.

First, you mentioned "backfire" and then dismissed this as not the problem. May not be the source of you smoke, but it doesnt sound good, unless you are running an uncorked header.

Second, you mention white smoke, but you dont exclude the usual valve guide/valve seal wear. This malady typically rears its ugly head upon deceleration. Burning oil can easily be described as white smoke as well as blueish white smoke. Since you did not distinguish the two shades of white, do you know the difference?