Hey, everyone I have a 72 FJ40 stock motor in it. H e i distributor i'm overheating out of nowwhwre... My radiator is 20° difference between enfeed out feed tested thermostat tested interior gauge flushed radiator found a plugged water jacket in the back with the drain I fixed that I do have a flex fan with a shroud. I'm still overheating. What else can it be? My timing is good at about 15° before top dead center..... Infrared heat gun shows about 170 all the way down the head.But my internal gauge is showing 230.... What else can I check and how
Another overheating post
- Thread starter Crusher 72
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Your stock gauge can be off/not accurate. Take your IR gun & measure top of radiator & the bottom also. Measure the radiator fins & along both sides of the head on the engine.
You’ve got to get accurate information & your stock gauge might not be giving it to you.
You’ve got to get accurate information & your stock gauge might not be giving it to you.
- Thread starter
- #3
Hey John, thanks for the reply. I have a stock and an aftermarket gauge. I've put the negative to the motor and the gauge bottoms out. So I think my gauge is good.
The ir gun from the top of the radiator to the bottom shows twenty degrees difference , which I think is normal
- Thread starter
- #4
Should The head read the same as the Gage inside.When you're reading the head with an I r gun
Measure the top of the thermostat housing. It should be close to the rating of the thermostat, 180* or so.
Is it boiling over or just the gauge says its running hot? Do you run window screen in front of the radiator? It will keep bugs from blocking the air passages. Do a compression test to make sure the head gasket is still good.
Trust your IR temperatures from your IR gun…do not trust stock dash gauges.
Warm your engine up & post temps from your T Stat housing…using your IR gun.
Warm your engine up & post temps from your T Stat housing…using your IR gun.
- Thread starter
- #8
T stat is 142.....top rad.hose 130...bottom hose 110.....gauge reads 245.....when I ground the gauge out it bottoms out 260plus.....the gauge rises slowly....tested temp sensor resistance and it chamged with heat and cold....so temp sensor bad?
Well I say your senders, wiring, or gauges are bad. I would let it cool off for a while, then open the cap - make sure there is coolant well over the core. Start it up and watch to make sure the level surges up and down as the thermostat cycles.
I would try to get/install a new gauge. In the meantime check it frequently with your IR gun.
Typically you can trust your IR gun. But what I do for a ‘test’ is to boil some water on the stove & verify boiling point with your IR gun. 212*.
Typically you can trust your IR gun. But what I do for a ‘test’ is to boil some water on the stove & verify boiling point with your IR gun. 212*.
Have your burped the cooling system? Use a drip free radiator funnel. Squeeze the upper radiator hose gently while it's running to help burp the system. I'll loosen the temperature sensor near the carb and let the air out there as well.
Your thermostat housing should get up to 180*, that's the only place I would be concerned with temperature. If your t-stat is broken you will likely get cool temps. Best to verify the t-stat is functioning properly.
Your thermostat housing should get up to 180*, that's the only place I would be concerned with temperature. If your t-stat is broken you will likely get cool temps. Best to verify the t-stat is functioning properly.
If you found one plug, you probably have more. You probably have sludge deposited in the the core of the radiator too. It used to be routine maintenance to have your core "rodded out" at your local radiator shop every 50 years or so...
If you're still running the original radiator, I'd have it thoroughly cleaned.