That's too much information to digest. What diagnostic steps led you to the thermostat? Is the radiator fan turning on? How long does it take to overheat;, ... Minutes, ... Hours?
Has the chemical test been done to check for a leaking cylinder head gasket?
Saturday, April 12th, 2014 AT 12:33 PM
Fan not coming on checked relay relay good what would you think I should check next
Saturday, April 12th, 2014 AT 2:27 PM
That's good news because of all the possible causes of overheating, diagnosing and repairing a dead fan is one of the least expensive repairs. First spin it by hand. If it's tight, replace it and check for a blown fuse or fuse link wire. If it spins freely, the motor still could be bad, but first check the fuses, and if there's voltage on one of the wires.
Due to a recent major house fire, I can't page through a service manual, so I can't give you specific wires to measure. At least one in the connector should have 12 volts, either whenever the ignition switch is on or when the engine gets hot. Another wire should have continuity to ground.
Also look in the under-hood fuse box for a fan relay. There could be two of them; one for low speed and one for high speed. A quick test is to remove the cover from one of those relays, reinstall it like that, then squeeze the contact. If the fan runs, you know the wiring and fuse for that circuit are okay. Try swapping the relay with one of the other ones like it.
You may need to find a mechanic with a scanner. That will allow you to command the Engine Computer to turn the fan on. Doing that allows you to test for voltage to the motor