Also agreed that you have an ignition problem. These old trucks have no protection strategy in the software like newer trucks do so the only way it would shut down on it's own from overheating is when the rings seize to the cylinder bores.

 

Are you sure you burped the system well...I've already seen 2 or 3 threads on here where everything has been replaced and they're finding out they had a big air pocket in the engine causing to run hot.

 

Earlier in this thread it was mentioned that the upper hose shouldn't be hard when warm, what does that mean?

 

If the engine is hot, but the top hose is NOT firm, that usually means a stuck shut thermostat. When the engine is at normal temps, the top hose will be firm, it will have about 15 psi behind it (or whatever your rad cap is rated).

 

Oh good, my thermostat should be good it was replaced recently. I think my fan clutch is bad though.

 

Have you pressure tested or vacuum tested the coolant system? I always prefer using a vacuum filling system to help avoid air bubbles. But a pressure test would still tell a lot about the condition of the coolant system. You can rent a pressure tester at any auto parts house usually.

 

Did the tin plate behind the water pump get installed when you put on the new pump.

 

What makes you think the fan clutch is bad? If it overheats while driving at a decent speed, like around 40 mph or above, then I doubt it's your fan clutch.

New thermostats can be bad, especially if you let the parts guy sell you one of those "fail-safe" ones. By the way, you did put the thermostat in the right way didn't you? Spring facing towards the engine. If you put it in backwards it won't sense temperature correctly and won't open.

 

Did this ever get fixed?

That was pretty good thinking by dixie460. Common enough to do. The "sensor" has to be on the correct side to work and it's easy to put the thermostat in backwards.

Did you ever try just removing the thermostat to see if it still overheats?

 

Is the thermostat in the right way? Kind of sounds like it may be installed the wrong direction blocking coolant flow.

 

Dumb question.....is the thermostat upside down??? I've mistakenly put tem in the wrong way before......then it's kick yourself in the *** and say....."pay attention dummy"......lol

 

Deleted wrong thread. My phone hates this mobile version

 

I had an issue like this, the truck would overheat quickly but only under load. The issue was really simple. The bottom hose was collapsing when the rpm's went up. Check to see if the bottom hose is the issue. If it does not have the spring in there, it will collapse.

 

This thread was started 6 months ago, so I'm sure his issue is resolved. Like a ton of threads, we will never know, because he didn't update. I read through, and just want to emphasize that you never run without a thermostat. This is a common mistake people make, and can actual cause an over heating problem. Running without a thermostat lets the water cycle through the radiator much quicker, not allowing it to have time to cool.