I was on the hwy about a month ago and my 4runner overheated come to find out it was a leak in the radiator. I replaced the radiator and now still over heating put the heat on and still problem. There is white smoke coming out of the tail pipe. Should I replace the thermostat? Any help would be great thanks.

 

Have you done a compression check? Over heating the truck could have possibly warped/damaged the head and also the head gasket. Smell the white smoke coming out of the exhaust, if it smells sweet (like Maple Syrup) do a compression check.

If you don't feel like doing a compression check then you can do one of two things. Do an oil change, put the old oil into a clear container. Check to see if coolant separates from the oil. You can also check your coolant, if there are black/brown spots then that is a good indication you may have blown a head gasket. You can also check the t-stat to see if it's sticking closed.

 

The white smoke means a blown head gasket.

 

Not always, sometimes on initial start white smoke comes from my exhaust. Could be condensation...unless it's a continuous pour of white smoke that's why I suggested what I did above.

 

Okay, first things first. Like previously mentioned, when you overheated the engine you MIGHT have popped a headgasket and possible warped the head.
Do a compression check, cooling system pressure check and check all the fluids.

If you have oil/coolant mix then that is a defenant to a blown hg. If the white smoke smells sweet then that is burning coolant, yet again points to blown hg.

Don't run it, you could damage the block.

Which engine do you have?