Overheating 04

[Felix Gonzalez]

My 04 explorer 4.6 began overheating last weekend, but I noticed that at road speed, the temp runs fine. Also, when the temp begins to climb at idle(lights etc), if I rev the engine, it cools down.
I went ahead and purchased a thermostat and will install it in the morning, but I'm not completely convinced it's the problem.
Does this sound familiar to anyone?

 

[974X4BLACKSPORT]

Sounds like a lake of coolant flow at lower engine speeds. Check the water flow through the radiator at idle with the engine up to temperature but not under pressure. NEVER open the radiator when hot and under pressure you can get burned. STart the engine cold and let it idle up to operating temperature with the radiator cap off and watch the flow through the radiator when the thermostat opens.
A worn or rusted out water pump impeller can cause lack of water flow at low engine speeds.

 

[Felix Gonzalez]

Sounds like a lake of coolant flow at lower engine speeds. Check the water flow through the radiator at idle with the engine up to temperature but not under pressure. NEVER open the radiator when hot and under pressure you can get burned. STart the engine cold and let it idle up to operating temperature with the radiator cap off and watch the flow through the radiator when the thermostat opens.
A worn or rusted out water pump impeller can cause lack of water flow at low engine speeds.

Ok, sounds like something to look at next.

 

[brokkanic]

My 04 explorer 4.6 began overheating last weekend, but I noticed that at road speed, the temp runs fine. Also, when the temp begins to climb at idle(lights etc), if I rev the engine, it cools down.
I went ahead and purchased a thermostat and will install it in the morning, but I'm not completely convinced it's the problem.
Does this sound familiar to anyone?

Sounds like a bad fan clutch.

If you spin the fan and it spins without resistance it's bad.

 

[Felix Gonzalez]

Sounds like a bad fan clutch.

If you spin the fan and it spins without resistance it's bad.

Thank you, checked that while I put the thermostat on this morning. It was good.
So far it is holding temp fine. Guess it was the thermostat.

 

[Felix Gonzalez]

It looks like it was the thermostat all along. Thanks everyone for the help.