Just rebuilt my engine due to a head gasket repair, finally got it up and running. It runs fine as far as I know, I don't feel anything weird with it. When I stop driving white smoke comes from the hood. I narrowed it down to a bolt underneath the intake manifold. It's the second or third one back, and it's holding the intake and exhaust in place. I have a 2000 sport with the 4.0 in it.

 

How many miles on this rebuilt engine so far?

 

The engine has 217k, It started smoking as soon as I started it, so nothing new on it.

 

White smoke indicates that there is coolant leaking into the combustion chamber which means you either messed up the head gasket install, had bad gaskets, or you have a cracked or warped head. Look at the oil to see if its milky. If you can do a compression check.

You stated in your other lost that the engine rattles at 60 , white smoke is coming from your upper radiator hose, valve cover, and intake, and you drive a 2000 so the safe bet is that the head is cracked. Perform a compression test and you'll have your answer.