im trying to figure out why my 1991 ext cab 22re 4x4 toyota temp runs up normal then spikes when running down road to red then runs back normal after about 3miles that only happens first start does not after its been running new egine with about 1000 miles stage 2 cam and kith black pistions header with 2/1/2 pipe running 31/10.50/15s toyo mts

 

It sounds like temperature over shoot, toyota has a special two stage thermostat that`s supposed to fix the problem.

 

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

 

2 things check your antifreeze level and leaks if its low. Next check your thermo it might be sticking. What you need to do get it up to normal operating temp get it to start to over heat stop the truck check both of your coolant tubes from the engine one on top one on bottom. Now these should be the same temp after the thermo opens up completely. If one is colder then the other do your thing to make it cool down and stop then check your lines they should now both be at normal operating temp

 

I've had similar problems on my vehicles I replaced the thermostat 3 times thinking I got defective ones than finally got a new fan clutch and that solved all my problems.