What would cause a puff of white smoke?

Most likely it's vapor. This time of year there is a lot of moisture in the air. When the engine starts up, it's blown out and is seen as a cloud. When warm you won't see it. Now, if this cloud appears when starting a hot engine that's been run for a while, well, then you've got problems...most likely in the cooling system

Atomic bomb maybe?

In this case, I vote for the "onset of colder weather." If you live in the southern hemisphere, that might not be it.

In that case keep an eye on your coolant.

Here are the colors of smoke form an engine:

black - an overly rich mixture (too much gas, or not enough air) blue - oil white - coolant (or normal water condensation during the colder seasons) clear - normal

So with white smoke from a hot engine, you could have coolant leaking into one (or more) cylinder(s).

-D

problems...most

no, probably the valve guide seals are leaking and when it sets awhile, you have the oil that seeped down thru the guides burning out in the cylinders.this causes smoke that goes away quick as the little oil seepage is burned out. Replace seals. not easy. old john

problems...most

No johnny, Probably not!

White smoke is WATER or water/coolant, NOT OIL... That would be BLUE Smoke...

I'm no mechanic, I just lurk here from time to time to see if any issues concerning my truck come up ('99 F250 V10).

But when I read Thunder's (Gary's) OP, he said his vehicle AND his wife's vehicle were experiencing the same problem. Seems quite a coincidence that both would be suffering from the same engine malady that began at the same time? (If in fact there is an engine malady)

I couldn't begin to say what the cause may be for BOTH of the vehicles to start doing what they are doing, but there may be a commonality somewhere. Different gas? Some additive? Weather (which has been mentioned) ?

It just seems to me that the likely hood of two different vehicles coming up with the same "problem", at the same time, is about as likely as the Boston Red Sox overcoming a 3 game deficit in the ALCS, and then going on to sweep the Cards in the World Series.... Oh wait, I guess it *could* happen :)

D>No johnny, Probably not!

yep, i never picked up on the WHITE smoke. old john

cylinders.this

||No johnny, Probably not! || ||White smoke is WATER or water/coolant, NOT OIL... That would be BLUE ||Smoke...

At a glance oil smoke looks white. I see it every day, and it's not steam ;)

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||> > Reece Talley wrote: ||> > > Most likely it's vapor. This time of year there is a lot of moisture ||in ||> the ||> > > air. When the engine starts up, it's blown out and is seen as a cloud. ||> When ||> > > warm you won't see it. Now, if this cloud appears when starting a hot ||> > > engine that's been run for a while, well, then you've got ||> problems...most ||> > > likely in the cooling system ||> > >

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Texas Parts Guy