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Smoke at start up


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mturnerua's Avatar
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September 10th, 2010, 3:34 PM   #1  
Smoke at start up

I have noticed that when I start up my 07 Tahoe I get a puff of smoke on occasion but I cannot readily replicate it. I live in Alabama and its about 90 degrees so I don't think it is a temp issue. I have also received a "low oil" message and have added about a quart of oil. One problem I have is that I've only had it a month and have not had the oil changed so its kind of hard to get a completely accurate reading of how much oil I'm actually using. Is there anything that normally causes this or that I can check? It has 95k on it so if it is something that is covered by the powertrain warranty I want to get it checked out quickly. Also I recently had the fuel injection cleaned so they might be some of the carbon burning but I had noticed the smoke a few times before that. Thanks

 
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September 10th, 2010, 4:02 PM   #2  
A small amount of smoke at start-up and the fact that it's consumed oil is an indication of valve guides going bad. While the engine is at rest residual oil at the top of the head along the valve train leaks down via the valve guide and collects in the cylinder. Once the engine starts it immediately burns this residual oil hence the puff of smoke.

A compression / leak down test can confirm this.

 
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September 10th, 2010, 10:04 PM   #3  
Not sure how a compression test or leak down will check valve guides since the valves are closed when you get a reading. Comp. check is for rings/cyl walls and valve seats.

Now the valve guides could be worn but I'd first suspect the valve seals. Not sure what these new engines use for valve seals.

 
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September 13th, 2010, 9:39 AM   #4  
So is there a test the dealer can do to confirm the problem or am I going to run into the issue of having to reproduce the smoke, which I can't always do?

 
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September 13th, 2010, 10:17 AM   #5  
Probably have to leave overnite so they can see it upon start-up. That's usually when you'll see it if it's valve seals/guides.

 
AHall's Avatar
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September 15th, 2010, 4:39 PM   #6  
Most importantly, get this resolved BEFORE your warranty expires!!!

 
mturnerua's Avatar
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September 15th, 2010, 5:09 PM   #7  
So I dropped it off at the dealer last night to let it sit over night. Lucky it "smoked like a freight train" the service guy said when they statred it. He said they did some test and the PVC valve is defective. They are ordering it and some seal that they will be replacing tomorrow. Hope this fixes everything.

 
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October 21st, 2010, 11:09 AM   #8  
Posted By: mturnerua So I dropped it off at the dealer last night to let it sit over night. Lucky it "smoked like a freight train" the service guy said when they statred it. He said they did some test and the PVC valve is defective. They are ordering it and some seal that they will be replacing tomorrow. Hope this fixes everything.

Just wondering how this repair worked out for you and what the seal was they replaced?

 
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October 21st, 2010, 11:12 AM   #9  
Posted By: zr800 Just wondering how this repair worked out for you and what the seal was they replaced?
I believe they replaced the PVC valve and seal and the valve cover seal. It has not had any smoke or oil loss since the repair.

 
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