: occasional white cloud from exhaust upon starting



wamanning
10-03-06, 06:06 PM
sometimes after sitting for a while and i start my '01 catera, there's a puff of white coming from the tailpipe that goes away immediately. doesnt smell like oil. i checked the coolant overflow and no evidence of oil. engine runs fine otherwise.

what might this be?

i'm digging around the forum and it looks like it might be a bad head gasket - thoughts?

how would one diagnose this?

if it is a bad head gasket, what are the risks if i leave it alone for a while? what happens if/when it gets worse?

guardian
10-04-06, 09:41 AM
Sorry bad news:

What can cause white smoke from the exhaust (http://www.faqfarm.com/Q/What_can_cause_white_smoke_from_the_exhaust)

I agree it could be a failed head gasget, or a failure of the head gasget to seal properly. You have to remember the Cat has aluminum heads. If your car has overheated at some point, well, that's not good. Cat head gasgets have to work especially well to accomodate the different coefficients of expansion between the aluminum heads and the cast iron block. Never allow a Cat to overheat. Never.

How many miles do you have on the engine??

wamanning
10-04-06, 09:49 AM
How many miles do you have on the engine??

just turned over 55K miles (~88K kilos).

aldi
10-04-06, 10:18 AM
If the engine is not loosing coolant, then it's not the head gasket.
I think it's only condensation water in the muffler, that's evaporized by the exhaust gases.

wamanning
10-04-06, 10:39 AM
thx...good news.

even so, i'll keep an eye on this.

FWIW...the vapour has no discernible odour and dissipates very rapidly.

guardian
10-04-06, 11:10 AM
just turned over 55K miles (~88K kilos).

OK.

Such low miles does not mitigate in favor of a failed head gasget unless the car has overheated badly.

I agree any car can throw off a little water vapor when it first is warming up. You are more likely to see this as the weather cools. But also you should be able to sense the difference between water vapor and burning anti-freeze. If it's white SMOKE it is most likely coolant.

Keep an eye on it. Watch your coolant level carefully.

Vesicant
10-04-06, 01:28 PM
White smoke can also mean its running rich on startup. The ECU can momentarily run rich to have proper ignition, and once the readings come in from the o2 sensor, maf and etc. it will run at a proper mix. Do you notice if it runs rough after the initial startup or takes longer than average for the engine to catch?

Our Catera (roughly 65,000mi on the engine) was doing the same thing upon startup, but since the check engine light was on it needed a new o2 sensor and it could be that- but we sold the car off recently.

It could also be condensation...

I doubt its a headgasket, usually those continue to emit white sweet smelling smoke (Burned coolant) after startup.

Warez
10-07-06, 11:36 PM
If the engine is not loosing coolant, then it's not the head gasket.
I think it's only condensation water in the muffler, that's evaporized by the exhaust gases.

My cars all do the same and its only more noticible now that the weather is getting colder.