I am looking at a 66 mustang with a 289. When the engine first first up, puffs of white smoke come out the back. When the engine is rev'ed up, more white smoke comes out. After it has been sitting for awhile it eventually gets better. I dont think it is condensation because it is the middle of the day with 75 degree weather. If it was coolant leaking through the head gasket why would it be smoking when it is first started? Wouldnt the thermostat keep the water in the radiator until it warms up so there wouldnt be much water in the engine? I checked the oil after awhile and it seemed to be at least half an inch above the "full" line. I heard too much oil could cause white smoke. The engine seems to run pretty good. There is an occasional miss when the rpms turn up fast but that may just be timing. Any ideas?

 

oil is blue smoke

 

Does the smoke smell like coolant? If it is coolant (and I'm betting it probably is), it could come from a lot of places. Head gasket, intake gasket, cracked head, cracked block, etc. It smokes when it's first started because after it's been running and you shut it off, the cooling system is still pressurized and there is no compression in the cylinder(s) to hold the pressurized coolant back anymore. It's probably NOT an intake gasket because of this but it could be any of the other things.

If the smoke actually does have a blue tint to it, it's likely oil and the motor needs a valve job or valve seals at the minimum.

 

Are you losing coolant? That would be a tell tell sign. Running really rich can also create a bit of a fog from the exhaust. What does the white smoke smell like?

In a real bad case, the cylinder compression can actually pressurize the cooling system pushing oil into the coolant and causing the radiator cap to blow out coolant from too much pressure.

 

My money is on bad valve seals, 289s are infamous for them.