I would start by checking the level of coolant in the reservoir right now,
then before and after every trip. Monitor over several trips. If you see it
going down, right away start carrying extra coolant in a jug in your trunk,
preferably Honda OEM. If it continues to go down, stop driving the car,
because the likelihood is high that the head gasket is failing, and your
engine is not getting enough cooling. The engine can be seriously damaged.
Watch your dashboard's temperature gage very closely. Do not drive this car
if it's high.

With a failed head gasket, you're looking at a $600 to $1000 repair or so.

Keep checking back, as there might be other causes. But with a lowering
coolant level, this one is pretty likely.

Google for {"white smoke" civic} for more discussion. Then google for {"head
gasket" symptoms} for other things you can check to see if the head gasket
is failing, like coolant in the oil system, and oil in the coolant system,
and the white smoke smells sweet, like anti-freeze.

If it's a failed head gasket, then I believe the white smoke is steam. I
would expect it to be more plentiful after the car is fully warmed up, since
it takes high temperatures to convert coolant to steam.

Updates welcome.

<matthew_jamees@hotmail.com> wrote
> I have a Honda Civic 94. For the past two days, when I drive 10
> miles from college back to my home and start the car after 15 or 20
> minutes, my car shudders a lot and I see lots of white smoke from my
> exhaust. After this when I drive, the smoke gradually goes away after
> one minute of driving. If I leave the car and start it the next morning
> (a gap of 12hours) or start from college back home (a gap of 10 hours),
> there is no smoke but the car shudder very very lightly. It is not cold
> here now in San Francisco.
>
> Can I know the reason why there is smoke only when I start the car
> after letting it cool for some minutes after driving for 10 miles and
> not leaving it off for a very long time. I am a student and on a very
> tight budget to spend on the car for repairs. So I need this groups
> help to know what the problem is so that I do not get ripped of at the
> garage. Can I also know what to check in my car.
>
> Matthew
>