Thermostat Question

[Randy88FJ62]

Hey Randy,

Someone makes a radiator cap with a thermometer built in. I think you can get them from Summit Racing. It's a quick way to determine if you're really running hot.

Good luck - Seth

Brilliant. I'll have to look for that.


I'm still looking for someone who can explain the cooling system on a 3FE better.

We have a water pump that circulates the coolant, a thermostat controls the flow of coolant based on temperature and the copper shim contracts and expands based on the temperature of the fluid. The rest of the cooling system is hoses and passages right? Since I have a new radiator and a new water pump the only thing I can see going wrong is the thermostat.

 

[Cruiserdrew]

In the 3 minutes I've spent looking at the 3FE thermostat housing, It looks like the sender is in the lower part of the housing just below the outlet pipe. In 2Fs the sender is in the head, so this is a departure for Toyota. There are 2 temp sensors, one for the dash gauge (the cheap one), and one for the fuel fuel injection (the expensive one).

At running temp the top of the radiator is going to be at the temp of the coolant coming from the motor-so that's 180-200 degrees, so hot enough to burn your fingers. You can check the temp of the radiator with one of those IR heat guns. Keep your OEM radiator cap.

 

[cruiser88]

Hey Randy,

Someone makes a radiator cap with a thermometer built in. I think you can get them from Summit Racing. It's a quick way to determine if you're really running hot.

Good luck - Seth

I seen one at a Advance Auto parts one time......should have picked it up just for the hell of it

 

[jvazquez53]

You did not solve the actual problem . Why was it overheating initially?

Don't know, I think cleaning the radiator with solvent and adding grease to the fan clutch helped, all I know is that the truck is running great now!! I learned from a gringo supervisor a few years ago that "if it ain't broken, don't fix it!"

 

[jvazquez53]

I did some FSM reading last night and I found that the thermostat is above the water pump in the "thermostat housing" at the front of the engine block right behind the radiator and above the belts.

Haven't chased down the sender location but I think it goes into the water pump.

QUESTION: When I turn my engine off and open the hood, the radiator is so hot it can burn my skin if I leave my hand on it. Is this normal or is this part of my problem with the thermostat staying closed/open and not circulating coolant into the engine?

2F, top left side, near the carb.

 

[cruiser88]

2F, top left side, near the carb.

What carb?


He has fuel injection.

 

[jvazquez53]

Oops, forgot that he has a 3FE, my 80 has a 3FE, I'll look tomorrow. Life is simpler in a 2F.