1992 Chevy 1500 Startup Smoke

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GILBERT011
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Last friday i noticed that my truck emmited a white/ slightly grey cloud of smoke throught the exhaust. This was at start up. I then went to check the exhaust tip for any deposits of sute, but it was clean (not black on my finger tips). So I reved it up a bit to see if some more smoke would come out, just a bit more came out, then when I took off it went away. While driving it does not smoke, but if i park it for a couple of hours and then go to start it, it smokes again just like i mentioned before. I hardly don't use this truck, I just have it as a back up vehicle. When I got it 3 months ago i replaced the pcv valve, o2 sensor, plugs, plug wires, belts, belt tensioner, I changed all the fluids and oil, new filters, radiator flush. I even had the engine bay degreased. Then I just had it sitting there up until 9 days ago. My mechanic cousin says it could be some bad pison rings that are letting oil seep in. Any clarification on this would help. thank you.

gilbert alvarez
odessa, tx
Aug 16, 2006 at 7:07 AM
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MIKEYBDMAN
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[quote:a81e2a60de="gilbert011"]Last friday i noticed that my truck emmited a white/ slightly grey cloud of smoke throught the exhaust. This was at start up. I then went to check the exhaust tip for any deposits of sute, but it was clean (not black on my finger tips). So I reved it up a bit to see if some more smoke would come out, just a bit more came out, then when I took off it went away. While driving it does not smoke, but if i park it for a couple of hours and then go to start it, it smokes again just like i mentioned before. I hardly don't use this truck, I just have it as a back up vehicle. When I got it 3 months ago i replaced the pcv valve, o2 sensor, plugs, plug wires, belts, belt tensioner, I changed all the fluids and oil, new filters, radiator flush. I even had the engine bay degreased. Then I just had it sitting there up until 9 days ago. My mechanic cousin says it could be some bad pison rings that are letting oil seep in. Any clarification on this would help. thank you.

gilbert alvarez
odessa, tx[/quote:a81e2a60de]

Sounds to me like your valve seals are starting to leak a little. Smoke on start up and then goes away while driving is a sure sign of this. The fact that the truck sit more than it is driven could have lead to this condition.
The solution is two fold. Dont do anything, and I doubt it will burn enough smoke to even make the oil low between oil changes.
Replace the valve seals. All you will need is an adapter to allow you to pressurize each cylinder. A spring removal tool, and new set of valve seals.
Remove both valve covers, and valve lifters. Pressurize one cylinder and remove the springs. Replace the seals, lube well, and reinstall the springs.
CAUTION! Do not remove the springs without the cylinder pressurized. If the valve falls into the cylinder, you will need to remove the head to reinstall it.
Aug 16, 2006 at 8:36 AM
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GILBERT011
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thank you for your quick response I really appreciate it.

Again thank you.

Gilbert Alvarez
Odessa, TX
Aug 17, 2006 at 1:24 AM

Suggested Repair

White-gray smoke only at startup that clears while driving points to leaking valve seals, possibly worsened by long sitting. If oil use stays low, monitoring may be enough. Otherwise replace the valve seals with the cylinders pressurized so valves cannot drop into the engine.

Conversation Summary

A 1992 Chevy 1500 that sits unused produces a white to slightly gray exhaust cloud at startup after sitting a few hours, then the smoke clears while driving. The exhaust tip is not sooty, and recent maintenance included the PCV valve, oxygen sensor, plugs, wires, belts, fluids, filters, and a radiator flush. A relative suspected worn piston rings, but the expert said startup-only smoke is typical of leaking valve seals and advised either leaving it if oil consumption is low or replacing the seals with each cylinder pressurized.

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