I dont have a catalytic conv. on my car and is has white smoke during startup and low speed driving. i do not think it is runnin lean but it may be burning antifreeze. Could not having the catylitic conv. produce white smoke?

 

No. The gasses that the catalytic converter is designed to absorb (for want of a better term) are not visible ones, so the white smoke you see is a byproduct of something burning that shouldn't be. The chances are that as it's white smoke, it's water/antifreeze.

 

Could be a light blue(oil). Give it a quick smell. If you are running antifreeze, it will smell kinda sweet if it's 'burning' antifreeze.

 

Smoke on start up on SBC = VALVE SEALS.....

 

corection: BLUE SMOKE on start-up= Valve seals

white smoke is coolant

and black smoke means your running too rich

 

If happens in cold or damp weather & goes away after the engine warms up, it's normal condesation burning off & yes it does happen without a converter. White smoke before & after warmup would be antifreeze & as said above, has a "sweet" smell.

 

Just because it's white doesn't mean it's water/antifreeze. It's a good chance, but it's not etched in stone that it's water/antifreeze.

I have an '83 C10 with a 305, and EVERY time I start it, it blows white smoke. And yes it's white. White as the pure driven snow.

I know it's oil. It smells like oil. Plus I have to add about 1 quart every 4-5 times I drive it (I don't drive it often).

I've had the truck for 1 yr. and the coolant hasn't gone down at all, so I know it's not that.

Do the smell test. If you have to, put a rag in front of the tailpipe while someone else starts it up, then smell the rag. It's safer that way.