Hi, my name's Ben. I recently bought a 2006 Commander 4.7 2wd. Previous owner was a mechanic whom rebuilt the motor due to an overheat from the owner before him. When finished rebuilding, he discovered a bad oil leak, didn't have a personal garage to work on it while Pittsburgh faced a brutal winter. He got fed up, and sold.
I fixed the oil leak ( melted air intake manifold ) then discovered overheating and white smoke from exhaust.
Ben welcome to the forum, I'm going to merge your other thread with this one - and then I'll try and answer some of your questions.
O.K. now that that's done, here we go.
White smoke coming from the exhaust is usually a sign of worn piston rings - which happens on higher mileage engines, although your mileage is not THAT high, so, I'm a little surprised you are seeing this already - this could also be a sign that your engine was not maintained that well over the years, IE not having the oil changed every 3,000 miles etc.
The worst case scenario would be that you have a cracked cylinder head - or a cracked engine block which could also be the result of the engine overheating on previous occasions - possibly prior to you buying it. If this turns out to be the case, your only option would be to replace the motor or the cylinder heads, whichever is cracked - or sell it as is and try & cut your losses.
The overheating could be caused by a number of things - bad water pump, a cracked radiator, a bad cooling fan - or it could be something as simple as a bad thermostat that needs to be replaced which is very minor.
Here are a couple of questions for you - are you seeing any DTC's (diagnostic trouble codes) being generated in the EVIC (Electronic vehicle information console)?
Have you noticed if you are leaking any coolant at all? Have you had to add coolant to your radiator or overflow tank recently?