ok, i got 72k on car and 25 year old valve seals. curious thing is, when she fires up on first click, there is no smoke. if it cranks for more than 5 seconds, the idle comes up slowly and it blows smoke. any ideas? had a car with a bad trans modulator that sucked trans fluid.

 

what color is the smoke? what oil weight are you using?

 

white smoke. probablly 5/30 regular oil, dealer changed oil before i got it. its due for a change. i use only full syn in my vehicles. just got it in may this year. it has new plugs and PVC valve. TPI engine new experience for me. did carbs for years. seen a bad PVC do something like this

 

white means its burning water, not oil. I'd pull the plugs and see what they look like. 1 or 2 shouldn't look like the rest. IF they all look the same, leave the plugs out. Pressurize the cooling system and crank engine(take out ecm fuse). You'll see water shoot out of the spark plug hole.

 

it smells like oil. and only on startup. i`ve seen what a blown gasket does.
how can water get in there?

 

a broken intake gasket by the water port can leak into a runner. Does the smoke look blueish?

- did the car have regular oil in it? did you switch to synthetic and notice any oil leaks?

 

smoke is all white. changing oil next week. not a drop of oil on floor, nothing. it would smoke all the time if water was getting into it. no liquid blows out the back but its always sluggish coming up to idle when this happens. leaking gaskets and aluminumn heads, gonna be a big headache. gotta know for sure, i`m getting too old to just tear a car apart looking for probs. do need to change thermostat, old one has to be stuck open, this thing never reaches 185 when moving. i have an old radiator pressure testing kit, will try it out. but since May, did not need to add coolant.

 

More common is a blown head gasket adjacent to the cylinder bore
Vette alums head motors are known for blowing on # 7 cylinder

 

with a blown head gasket, it gets parked. loan payments keep me from doing anything.guess i`ll try to unload it.

 

When my head gasket blew I got water on the exhaust manifold when I cranked it over while doing a compression test. Pull out the plugs and see what you get.

Corvettes don't have trans modulators, so you don't have to worry about that...

 

How long does it smoke? Maybe flooded from cold start injector if you have one?

 

sure is a lot of "doom & gloom" ! !

last time I checked, MOST ALL late model engines puffed some white smoke at start up depending on the geographic location, humidity and ambient air temp. Less noticable in summer, its plain obvious in winter. We see it everyday. It stops when the engine/exhaust gets warm.
Condensation. From wet air or wet/cold air...

Do this to eliminate the feared head gasket...

Take the rad cap off.
Take the serp belt off.
start the engine and rev it. Look in the rad opening. If the water moves, you have a blown head gasket. If it just sits there...there is nothing wrong with engine gaskets.

By doing this you completely disconnect the water/coolant from any moving parts in the engine. The ONLY way it can move is by engine compression or exhaust..air pressure of some sort. Water pump is not turning...

If you are not missing water or oil,. ignore it. Many Gen-I sbc have leaky valve seals. MANY folks LEAVE 'em and tolerate the brief (very brief) puff of blue smoke...its upper cyl lube at cold start up where there is NO oil circulating...so what exactly does this drop of oil harm??????
NOTHING.
You want upper cyl lube at cold start. Your engine will thank you when it clocks an extra 100K.

As usual, the full displaimer follows....

IMHO.

 

If it goes away after the motor warms up, it's condensation.

 

It could be a little oil getting past the oil ring. No big deal until it starts burning oil excessive. Change the oil, see if you need to add any after 3000-4000 miles. If you have to add more than a quart, there may need to be some repair performed, if not , drive on.

 

Even if a quart in 2000 miles who cares and why. It will not slow the car down or cause any real problem. It amazes me how perfect some want to make a 25 year old car.

 

You said this only happens part time? when its cold? or hot? on a restart? how long does it smoke? how often does it have long crank/smoke? we need a better definition of the problem.

 

no bubbles or any odd action with radiator cap off. there is oil puddling at left side of thermostat. may be a coolant leak into runner. it needs a thermostat and have no idea of age of coolant. how about if i use stop leak before i change coolant and with housing off i can try to torque manifold bolts? with PVC off there is absolutely no blowby. the smoke/steam does`nt really smell like oil but there a big cloud of it. i know what early morning condesate looks like and its faint compared with what i`m talking about. and if i "get on it" there is nothing coming out. it does not do it when i start up in morning, just normal condesate burn off when it heats up.

 

If you want to test the cooling system go for it.
A little oil puddling is typical with these. Pull bolt out add sealer reinstall. Worst case replace intake gaskets, probably not needed.
My DD burns 1 qt/1000 mi always has since new runs just fine. Some just do it.

Id bet theres nothing wrong with it.
Dont go tearing it apart and selling it now

 

my first TPI engine, if it was one of my other cars, i wouldn`t even blink, rip about ASAP. and it is a DD. wouldn`t think of leaving it in garage, waited 40 years to get a vette.