Smoke Signals

[jkeldridge]

So I've got a 2005 Suburban 5.3l. The thing blows billowing majestic clouds of white smoke when I start it after it's sat for a while...I mean like fog machine at a rave levels of white smoke. Cold days, hot days, humid days, doesn't matter. The smoke usually clears up in a minute or two.

I tested the block, which came back negative. Now I'm thinking it's possibly the intake manifold? I think my lousy mileage (13.4mpg on the highway) supports this, but I'm open to more ideas. The only trouble code I have is P0128, which I plan on remedying with a new thermostat this weekend, but I can't see that having anything to do with the smoke signals I'm putting out. Help please!

 

[Scottydoggs]

does it smell like oil burning? typically that would be valve seals gone bad letting oil drip down the valves into the cylinders.

white is coolant most of the time, might have a sweet smell. then you looking at a bad head gasket.

say you had the block tested? what was tested?

 

[swathdiver]

So I've got a 2005 Suburban 5.3l. The thing blows billowing majestic clouds of white smoke when I start it after it's sat for a while...I mean like fog machine at a rave levels of white smoke.

Gotta pull the heads Kimosahbe! Check for Castech cracks, bad head gaskets and or valve stem guides worn and take it from there.

 

[jkeldridge]

Standard block tester - like this https://www.amazon.com/Block-Tester-BT-500-Combustion-Leak/dp/B06VVBSFTF

Would valve guides/seals not give me a trouble code?

 

[Scottydoggs]

so that test tells theres no exhaust gas in the coolant. thats good.

no you wont get a code for a bad valve seal, it just leaks oil down the valve stems. not sure how common they are to fail on these engines, unless you got hi miles.