2006 Tahoe-White smoke on start up

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2006 chevy tahoe LT. It started to blow white smoke on start up when we had hot weather here 90 plus. Talked to mechanics at my work and they sugested valve stem seals . Did those but it didn't help. After a while i started to noticed small bubbles in the coolent reservoir. Shortly after radiator developed a crack and leaked (on friday the 13) added stop leak boubbles went away but not the smoke. Yesterday I checked the compression on passenger side heads 180,190,209,195 . 209 was wet spark plug. Tried to do leak down test. Piston top dead center and air in cylinder . Had air coming out of oil fill cap on 3 of the 4 cylinders checked, the fourth one i didn't do the leak down. Next week going to Mechanics for proper diagnosis. Otherwise the car drives fine. Engine is smooth no misfire or hesitation.
 

HiHoeSilver

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2006 chevy tahoe LT. It started to blow white smoke on start up when we had hot weather here 90 plus. Talked to mechanics at my work and they sugested valve stem seals . Did those but it didn't help. After a while i started to noticed small bubbles in the coolent reservoir. Shortly after radiator developed a crack and leaked (on friday the 13) added stop leak boubbles went away but not the smoke. Yesterday I checked the compression on passenger side heads 180,190,209,195 . 209 was wet spark plug. Tried to do leak down test. Piston top dead center and air in cylinder . Had air coming out of oil fill cap on 3 of the 4 cylinders checked, the fourth one i didn't do the leak down. Next week going to Mechanics for proper diagnosis. Otherwise the car drives fine. Engine is smooth no misfire or hesitation.

Any coolant loss or signs of coolant in the oil?
 

iamdub

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Pretty sure it's not smoke and it's actually steam and you either have a blown head gasket or cracked head. Maybe even the common 706 head failure. I'd pull the passenger side valve cover and rocker bridge and inspect around the head bolt holes for coolant or evidence of coolant. If it's a small leak, it won't necessarily make a milkshake in your oil. But it'll gunk up the entire inside of your engine until it chokes off the oil flow and eventually cause a loss of oil pressure and maybe wipe out your valve train. I have the pics and memories to prove it. Get it checked out ASAP while it's still an easy and much cheaper repair.

After it's repaired, as well as your radiator replaced, you're gonna need a strong coolant system flush to get that stop leak out.
 

Big Mama

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So this started a few months back? Next time you start it put your hand by the exhaust to see if it smells like oil or antifreeze. Are you noticing any oil loss? What Chris said above makes sense as the cooling problems pop up when it’s hotter out.
 

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Pretty sure it's not smoke and it's actually steam and you either have a blown head gasket or cracked head. Maybe even the common 706 head failure. I'd pull the passenger side valve cover and rocker bridge and inspect around the head bolt holes for coolant or evidence of coolant. If it's a small leak, it won't necessarily make a milkshake in your oil. But it'll gunk up the entire inside of your engine until it chokes off the oil flow and eventually cause a loss of oil pressure and maybe wipe out your valve train. I have the pics and memories to prove it. Get it checked out ASAP while it's still an easy and much cheaper repair.

After it's repaired, as well as your radiator replaced, you're gonna need a strong coolant system flush to get that stop leak out.

Exactly where I was heading next... unfortunately.
 

swathdiver

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I would say head gasket but those might be cracked heads too.

Wait, they did valve stem seals without pulling the heads? They didn't notice any leaks or think to check? Are these LS guys or Ford guys?
 

iamdub

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I would say head gasket but those might be cracked heads too.

Wait, they did valve stem seals without pulling the heads? They didn't notice any leaks or think to check? Are these LS guys or Ford guys?

I'm doubting their knowledge just based on them diagnosing and replacing valve stem seals from "white smoke" coupled with all the other symptoms that likely would've been noted during a half-assed thorough assessment.
 

OR VietVet

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If you are noticing the "white" smoke only on start up and not while driving it, I would guess that after engine is shut off and cooling down you are getting the start of head or head gasket problems and the initial smoke is what drips in to a cylinder or two that you burn on initial start up. I believe it will get worse and yes, when repairs are done get that stop leak flushed out of there.
 
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