Smoke at start up

[K9Gunner]

i have a 05 Yukon slt with 250,000 miles on it. Had it since new and it has been babied. I know it’s a lot of miles so I expect issues to start popping up. It’s had a small oil leak until it cools off after running. 4-5 drops each time in driveway. I have noticed when I start it up it puffs a large cloud of white/grayish smoke for a second. After that it no longer does it. It only happens after the car has cooled down. Any thoughts? Thanks.

 

[CountryBoy19]

If I had to guess (I don't have a lot of experience with this particular engine) worn valve guides leaking a little oil into the cylinders. When it's running the minuscule amount getting through is continually being burned off. But when it sits enough accumulates to make a noticeable cloud right at startup.

 

[Snowbound]

Sucking oil into intake from the drivers side valve cover. Common issue. A cheap catch can will solve this.


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[K9Gunner]

What is the fix???


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[Doubeleive]

lol

 

[SnowDrifter]

What is the fix???


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I'm thinking its valve stem seals. If that's the case, then replace them. It can be done without removing the heads, though it is a bit labor intensive.

There's a good write up below. Of note: Rather than using a compressed air tool to stop the valves from falling in, you can remove the spark plug, turn the cylinder to bottom dead center, fill it with some small diameter rope, then turn it over so the rope compresses against the valves. I'm not a huge fan of the air tool, personally. Any interruption in air supply and you're pulling the heads off

https://www.silveradosierra.com/how...seals-without-removing-the-heads-t636338.html

 

[the blur]

White is coolant.

 

[Knightstormz]

You need the updated drivers side valve cover.
My 2005 Avalanche did the same thing at startup.

It’s a quick job and worth the price of the part!

 

[K9Gunner]

Any brand I should go with or go with GMC?


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[89Suburban]

White is coolant.
Black is oil.

Black is too much fuel
Blue is oil burning
White is moisture/coolant burning

OP:

I have 310K on mine and it does the same thing I just drive it and keep it topped off and delete the AFM if you can. The oil catch can is on my bucket list too...

 

[CountryBoy19]

Black is too much fuel
Blue is oil burning
White is moisture/coolant burning
.

True but it can be hard to distinguish white from "blue" to the untrained eye.

 

[K9Gunner]

Now the Yukon is not smoking at all during start up. I have not replaced anything to remedy the problem. Any thoughts on why it would stop on it’s own?


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[Snowbound]

Now the Yukon is not smoking at all during start up. I have not replaced anything to remedy the problem. Any thoughts on why it would stop on it’s own?


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Out of oil?


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[K9Gunner]

Lol thanks for the response but I check it everyday. Still good on the oil part


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[Snowbound]

Lol thanks for the response but I check it everyday. Still good on the oil part


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Maybe the little orifice in the pipe coming off the valve cover is plugged. Start the engine and pull the oil fill cap and see if there’s any pressure or fumes coming out. Shouldn’t be when idling and pulling vacuum on PCV in drivers side valve cover.

I would still install a catch can but definitely find out if the hole isn’t clogged. I had to blow compressed air thru one one on my buddies 2010 Hoe because his valve cover started leaking and there was pressure when I pulled the oil fill cap.

I’d start there.


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[Rocket Man]

You need the updated drivers side valve cover.
My 2005 Avalanche did the same thing at startup.

It’s a quick job and worth the price of the part!

Have that part #? My 05 is doing this but I’m thinking it’s the valve seals.. I might try the valve cover though.

 

[Snowbound]

Have that part #? My 05 is doing this but I’m thinking it’s the valve seals.. I might try the valve cover though.

Sorry for the late response.

12642655 - COVER ASM-VLV RKR ARM (2009-2011 Truck)

12570427 - COVER ASM-VLV RKR ARM (2007-2008 Truck)


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