I Have A 92 Toyota With 545,000 Km {300,000 Miles} That Is Doing Wierd Things In Terms Of The Temp. If The Temp Control Is Set For No Heat The Temp Gauge React As It Always Has. If The Heat Is Turned Up The Gauge Reads Higher Than It Should But Will Reach A High Point Than Drop Back Down To Normal. I Have Had The Thermastat Changed. I Have Not Seen Any Leaks Of Coolant Or Any Thing Like That. Any Idea's Would Be Helpful.

 

Temperature gauge overshoot. It's a somewhat common problem on the 22r series motors. Installing the dual stage thermostat (part# 90916-03070) should alleviate the problem.

http://www.4crawler.com/4x4/CheapTri...tml#Thermostat

 

I think my 86 pickup my have that problem to let me know how it works for you?