I recently had a rebuilt 3.0 V6 (3vze) put in my 95 4Runner. It ran fine for over 1500 miles and is now overheating on simple 10 mile commute home. Oil was changed at about 500 miles and fluids are checked regularly. Any ideas why it has started overheating?

 

Bad thermostat? Air in teh system? Does it overheat then cool down, overheat then cool down? (you would need to burp the system)

 

It overheats when sitting still, if I am moving the needle goes right back down. How do you 'burp' the system?

 

don't know how it goes on the 3.0 but on mine with the 22r place the front of the vehicle up on ramps remove the rad cap and run the motor with the heater on until the thermostat opens. run it for a bit and then add more coolant. run it again till the level does not go down. If you can it helps to squeeze the lower rad hose while the engine is running to help the air out.

You might have a bad thermostat as well.