hey guys , well when i start my truck the needle shows cold then it runs for about 2 or 3 minutes and it pegs hot,there is no middle it goes from cold as ice to pegged hot, i turned off my truck and the coolant in the radiator is still cold to the touch, any ideas?

 

Thermostat, does it have the bleeder hole? if not it might have an air bubble that collected under the stat.

 

another guy said it might be the temperature sending unit does that sound right.. cuz it just goes from cold and raises all the way up in like 2 seconds..it runs fine and then from dead cold just raises straight up to pinned hot

 

Its possible it could be the sending unit, but I recall they had a similar problem years back with needle spike on the temp gauge and Toyota had a upgraded thermostat that replaced the stock one that cured the problem.
Air in the cooling system will collect under the thermostat cause it can't circulate past until the thermostat opens, the air gets super heated compared to the water and causes a false reading on the sender from what I remember. The bleeder hole thermostat lets the air and a small amount of coolant circulate past.

 

Here I found it for ya, Toyota sercive bulletin,,,
TSB: 029032787 22R-E Engine Temperature Overshoot

It says:

Some 1984 pickup trucks and 1983-1984 Celica models, equipped with 22R-E engines, may experience a condition called "temperature gauge overshoot". After starting a cold engine the temperature gauge will indicate a higher than normal engine temperature for a short time just prior to the thermostat opening. After the thermostat opens, the temperature gauge will return to the normal range. A new double valve thermostat has been made available to reduce temperature gauge overshoot.

And calls for part number 90916-03070 which according to the TSB replaces 90916-03055.

 

well thank u .. you are a gentlemen and a scholar

 

so i replaced the thermostat and its doin the same thing.. any other ideas

 

Has to be the sending unit!

 

alright ill get that on order.. haha does anybody have pics of were it is and wat it looks like, i dont have a chilton

 

Flush your radiator ancheck all hoses for crimps or blockage. And maybe test the water pump?

 

Maybe try runnin it without a thermostat and see if it still heats up?

 

It kinda looks like your truck is body dropped, but its hard to tell with the tiny ass pictures this site provides. If it is, look to see if your radiator cap is lower than the coolant hose goes into the top of the motor. If it is, you'll have to burp it. By burp it, i mean, get the radiator cap higher than the inlet, then open it. I did it by lifting the front of my truck all the way up, and dropping the back all the way down. Burped it to get the air bubble out, and now its fine.

 

nope no body drop not yet but i will give that a try and see wat happens thanks guys