Diagnosing white smoke on startup

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TX87R10

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I have been reading on the forums to try diagnose this startup issue. When I start my truck first thing in the morning I'm always getting a pretty decent amount of white smoke. I am going to attempt to include a video from this morning.

I checked where I thought the PCV valve should be but to me it looks like one is not installed.

I smelled the oil and do not get a gas smell from it.

The white smoke does not have a sweet smell. I would say it is acrid. Since I got COVID a few years ago my smell is really poor but I know the smell of coolant and gas pretty well, I just can't seem to pinpoint what THIS smell is.

My truck does have a small coolant leak as well as some oil but I keep the fluids topped off.

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Link to startup video.

 

TX87R10

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If you're thinking coolant in any way then keep your radiator cap on half way so it don't build pressure. Try testing that way first maybe.
For what it's worth I don't think it is coolant, but I am not 100% sure. I checked the radiator and the reservoir and levels are good.

I can try to leave the cap half on but I'm assuming if that was the issue it would take a few days to be able to tell?
 

TX87R10

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If it is the valve guides and seals I'm assuming that would be oil burning. It only seems to smoke in the morning when I have not run the truck overnight and it cools down so that would make sense.

It is about 107 here everyday right now so presumably in the cooler temp it is allowing oil to pass thru but while in the middle of the day even if it hasn't run for a couple hours it will not be as noticable. Does that sound right?
 

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Run it without the radiator cap and if you don't see bubbles, probably not cracks or a head gasket. I'm still voting for valve guides and or seals. You can also try a "leak down" test to check valves and seats (valve job needed).
 

squaredeal91

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My 83 regal 305 smokes Blue on startup allot but not every time. I'm 99% sure it's valve guides. Seems to smoke more parking on level ground than on a hill. And it will do it after parking for 10 min or so. Like when getting gas or going to the store.
 

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I'm guessing valve guides as well. Wanna know why? Because I was part of a test years back that involved the V-22 Osprey. The purpose of the test is irrelevant but every morning when they fired the ol girl up, she poured white smoke like yours. When I asked why, the smart guys told me it was from oil that had seeped past the seals during the night. After realizing they stored it with the engines rotated in the vertical position, it made sense. As soon as it went horizontal and cleared out, it was good to go. I think they have since rectified the issue but an interesting conversation piece none the less. And BTW, I took the pic. Yep, I was standing there overseeing the data collection and took that photo. It has really made the rounds on the internet since 2008!
 

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DoubleDingo

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Pop is a mechanic from way back and he says these trucks did that. It's oil getting past the valve guides and seals. Mine did it too until I swapped on different heads.
 

HotWheelsBurban

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Do you have a better picture of the engine? The PCV valve should be in one of the valve covers. This is my '97 Vortec 350 but I think it's the same place on the TBI ones. Driver's side valve cover, see where the purple arrow is pointing. IIRC the AC part number is CV679C for the one without an elbow on it. Reminds me, I need to replace it on this truck....
 

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PrairieDrifter

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It's valve guides and seals. I had A LOT of smoke on startup, real bad after all night and pretty bad after any other normal amount of sitting. Also high rpm.

My cylinders are just about wore out, changed heads, no more smoke on startup or high rpm.
 

TX87R10

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Do you have a better picture of the engine? The PCV valve should be in one of the valve covers. This is my '97 Vortec 350 but I think it's the same place on the TBI ones. Driver's side valve cover, see where the purple arrow is pointing. IIRC the AC part number is CV679C for the one without an elbow on it. Reminds me, I need to replace it on this truck....
Ill try to get a better one but it almost looks like that hose is directly connected to a nipple to me. I don't see room between it and the cover for a PCV valve to be there which is what was throwing me off, I expected to see it right there
 

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Ill try to get a better one but it almost looks like that hose is directly connected to a nipple to me. I don't see room between it and the cover for a PCV valve to be there which is what was throwing me off, I expected to see it right there
on my 1990 TBI the valve is in the passenger side valve cover and connects to the front of the tbi. the driverside is just a plastic hose connecting the other valve cover to the base of intake below the air filter.
 

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I have been reading on the forums to try diagnose this startup issue. When I start my truck first thing in the morning I'm always getting a pretty decent amount of white smoke. I am going to attempt to include a video from this morning.

I checked where I thought the PCV valve should be but to me it looks like one is not installed.

I smelled the oil and do not get a gas smell from it.

The white smoke does not have a sweet smell. I would say it is acrid. Since I got COVID a few years ago my smell is really poor but I know the smell of coolant and gas pretty well, I just can't seem to pinpoint what THIS smell is.

My truck does have a small coolant leak as well as some oil but I keep the fluids topped off.

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Link to startup video.

WHITE smoke or blueish smoke? If it is indeed smoke and not steam, probably your valve stem seals - oil is seeping down the valve stems when the engine is off, and getting burned upon startup. OHV engines are notorious for this when those seals are gone.

James
 

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