Original 1987 V10 Silverado, 350/manual...my truck puffs out white smoke? on start up

[57NAPCO]

1987 V10 350 4 speed 114,000 original miles 100% original.

Needing a bit of help/opinion from the collective

I have owned this truck for a few years now and I notice on cold start up after sitting over night or for a few days it puffs out white smoke or possably steam, just on start up up , it does not continue to smoke that I can tell. By the time I run back to catch a wif it’s dissapated into the air. It runs fine, no issues. I figured if it was oil burn I’d smell it. Radiator fluid is clean, so is oil.

valve guides ?
Rings ?

Truck is up in Maine so I have no tools, just thought I’d throw this out there to see what y’all think.

Thanks

[68Gold/white]

A little oil is seeping past the guide seals, showing up when you start it. If engine runs as well as you describe, otherwise, I would NOT do anything to it.... a normal thing on engine of that age...
absolutely nothing to worry about...

[57NAPCO]

Originally Posted by 68Gold/white

A little oil is seeping past the guide seals, showing up when you start it. If engine runs as well as you describe, otherwise, I would NOT do anything to it.... a normal thing on engine of that age...
absolutely nothing to worry about...

Thank you, good words

[72cs20]

I had an issue like you describe with the tbi 350 in my truck. It turned out to be a water leak at the intake manifold. Water visibly leaking on the outside but also some getting into the combustion chamber on the inside, hence the white color coming out of the tail pipe.

A couple of months after I fixed the intake manifold leak I started getting a puff of bluish smoke out of the tailpipe at startup. Valve guide seals this time. Replaced those now all is good.

This all happened right around the 150k mile mark.

[57NAPCO]

Thanks 72, gonna look into that possibility

[68Gold/white]

The water leak is a fairly common deal on the throttle body 350/305's that began in 1987 and ended in 1995. IF, IF you are losing coolant, this is a place to look. Some times you will corrosion in area of heater connection before the leak begins.

If your intake gasket has never been replaced (if it were mine...) I would plan ahead time wise and replace the gasket. The intake is aluminum making things easier, but the aluminum can corrode easier, so look at the gasket mating surface on intake carefully before re-installation..........