white smoke on start-up?

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white smoke on start-up?

Postby lmilli1 » Sun Nov 17, 2013 4:35 pm

Hey guys and gals.
I recently got an '06 H3... Everything is going great except for the white smoke that comes out the exhaust on start-up. This happens when the truck has been sitting for several hours only. I have been researching, talking to folks, etc etc and I cant seem to pinpoint the problem. So, here I am in a Hummer forum hoping one of you can lend me your wisdom, and have had a similar issue. Here are the culprits I have explored and heard about thus far.....any thoughts would be GREAT:
-valve seals
-head gasket(I don't think that's it. After start up everything runs just fine)
-cylinders
-just normal?
any ideas? please be specific, I am new to Hummer :) Thank you!!
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Postby caljon88 » Wed Nov 20, 2013 10:53 am

Way back when I had an S10 that did that and a valve job fixed that. How many miles?

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Re: white smoke on start-up?

Postby marcanthonywebs » Wed Nov 20, 2013 10:49 pm

lmilli1 wrote:Hey guys and gals.
I recently got an '06 H3... Everything is going great except for the white smoke that comes out the exhaust on start-up. This happens when the truck has been sitting for several hours only. I have been researching, talking to folks, etc etc and I cant seem to pinpoint the problem. So, here I am in a Hummer forum hoping one of you can lend me your wisdom, and have had a similar issue. Here are the culprits I have explored and heard about thus far.....any thoughts would be GREAT:
-valve seals
-head gasket(I don't think that's it. After start up everything runs just fine)
-cylinders
-just normal?
any ideas? please be specific, I am new to Hummer :) Thank you!!


Are you sure its white or does it have a bluish tint to it? Usually if its a bluish tint then its burning oil which could possible be the valve guide seals, valve guide seals normally only suck oil in if the car engine is off (unless the valve guides have dropped then it will burn as long as the car is running), when the car is off the oil has to drain back into the oil pan so if the seals are cracked or dry rotted then oil will run down the valve into the engine so when you start it up the oil will burn in the cylinders until its gone.
I have also seen bad fuel injectors leak down into the cylinders and you will get a lot of smoke and the smell of raw gas upon start up
I seen too much negative crankcase pressure from bad vent valves, pcv valves causing a suction in the motor that pulls oil into the cylinders but this would burn smoke all the time
About the smoke if its white does it float like steam or a cloud? Possible water in the cylinders

you need to check your coolant level make sure its fine you may even have to use a marker to make sure the level is not going down gradually,
And do the same for the oil level and transmission and this may sound crazy but check the master cylinder level also I seen master clyliders leak fluid into the booste which then gets sucked into the intake to be burned
Sometimes Oem specs are Lame! Let's overdo it within reason :-p!
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Re: white smoke on start-up?

Postby lmilli1 » Sat Nov 30, 2013 10:16 pm

Thanks guys.....
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Re: white smoke on start-up?

Postby 6pack » Sun Dec 15, 2013 10:29 am

Any news? If it only happens on start up, maybe there is an external leak that is seeping into the exhaust manifold at the head. It builds up a little and gets blown out at startup. Maybe? Let us know what you find out.
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