1989 Toyota truck...Trying to help my buddy out. His truck is bone stock and otherwise runs great. It's got the 22RE, 5-speed.
It just randomely gets hot, not all the time, not even every day. His coolant is filled correctly, no leaking Head gasket etc. He says the weird thing is that it'll get really hot but run normally, no odd smoke or smells. Then after running hot for several minutes the needle drops to normall operating temperature really fast. The truck continues to run fine, usually this issue doesn't return again for another couple days. Oh yeah, he already tried a new OEM thermostat and a new OEM radiator cap.
Any ideas? A clogged heater core or something??
Thanks for any info.
Mark

 

It could be that the temperature sender for the gauge is going bad... that or the fan clutch.

 

Have a look at this page for some ideas, sounds similar to the 22RE Temperature Overshoot TSB:
- http://www.4crawler.com/4x4/CheapTri...tml#Thermostat