22re what would cause my temp gauge to go all the way to hot, when I use my heater? It goes all the way to hot, not quit till red, then it cools back down...If i dont run the heater it goes just alittle off cold and doesnt move...Any ideas?

 

Could be a gauge problem, thermostat problem, heater core problem.

I'd change the thermostat for a Toyota brand one to start with.

 

I would suggest having your radiator professionally flushed. These really get alot of crud in them and a home flush kit just doesnt get them clean. I would then flush your system.

Also, I am just guessing, that you have a rear heater in between the front seats for the rear passengers? I have found on this site that if you have that option that you need a Dual Stage Thermostat. I found a part number #90916-03070.

Other then that I would suspect your guage.

 

Take the wire off the temperature sending unit located on the side, I think, of the intake. Should be near the thermostat. It will be a single wire. Turn the key to the ignition to the on position, do not start. Ground out that wire you pulled, take a bare wire and touch it to the body of the sending unit. If the dash gauge goes to hot, your sender is good, if not your sender could be bad.
After that it may be the above mentioned problems. My truck did the same thing when I would start it. That wire will also gt corroded and produce more resistance since this a variable ground unit, more resistance equal bad readings.

 

RBX just reminded me of a problem I had. If you go to the link here, https://www.yotatech.com/forums/f199...9/index15.html on #353, my sensor was corroded up. I just pulled it and got the corrosion off and fixed it.

 

Some of these engines will do this It has to do with the design of the thermostat Drilling a small 1/8" hole in the thermostat will most likely solve the problem.

If it runs normal after that temp spike. Although it never hurts to check for other problems as well

I have seen threads on here about this issue