I'm visiting from the 6.0 forums cause I have a buddy that is having issues with his 7.3. He says that his truck is heating up when under a load. He said he's flushed the coolant system, replaced the thermostat and water pump but it still heats up. Is there something else I can have him look at that might be causing the problem?

Thanks for the help guys.

 

Oil cooler.

 

The oil cooler can cause it to overheat?

 

If its blocked up it can.
An aging fan clutch is another possibly.


Many factors can be contributors to an overheating engine...

Fortunately this engine is very simple to diagnose.

If there are no exhaust leaks/boost leaks...
Is the high pressure oil system ailing...?
Does the coolant system hold pressure?
Could the water pump be going out?

Anything that is a weak spot in the system can cause it to overheat when worked hard is the point... start with the cooling system and work from there... next closest assembly is the oil cooler.

 

Awesome I'll let him know. Thanks for the input Chris.

 

You may want to check the condition of the radiator for dust and dirt and bent fins!

Smokie

 

Radiator shops can inspect and or flow test the radiator. Since the pump is new, radiator and oil cooler are next on the list.

 

The radiator is the first thing I would check. It could be partially stopped up and restricting coolant flow. That will give the exact symptoms you describe.

 

also, what thermostat did he use? the parts store thermostats usually don't work, you need either a ford or international unit.

 

To explain the thermostat thing better: There is a small hole in the Ford/IH thermostat - this allows the air to bleed out and the coolant to reach the thermostat. The thermostat works correctly only when coolant is in contact with it.

 

I had the same problem years ago, swapped water pump x2, degas caps x2, thermostats x2, clutch fan.. still would over heat under a load. It was the radiator that was not flowing enough. It was partially plugged. I could run a garden hose up top and it would pour out the bottom. Never filling up or acting like it was restricted. But it was. Ill bet money it is his radiator.

 

easiest way to tell a plugged up radiator is with a hand held infrared thermometer.
shoot the core, and look for temp differences. the plugged area will be cooler than the flowing areas.

 

That's a lot of good things to look for. I will definitely pass it on to him. FTE is the greatest!

 

Tom, I love it when someone comes up with another need for a tool that I already have. Your idea for checking radiator temps is brilliant. The advantage with a radiator is that the black color of the radiator gives a precise indication on the infrared tester. Something shiny like a wheel changes the accuracy of the tester because of some obscure physics law which I don't want to remember. Thanks for that idea! Larry