Thanks! I burped it by parking on an incline and running it with the radiator cap off. That should do it, right? Get the air out?

 

I'll bet you need a new water pump; any idea age of the current one? With a new radiator & no stat it should be riunning cool. Why did you replace the sensors? Maybe new ones are wrong causing faulty reading?? Have you tried an infrared gun to verify temps?

 

My experience with engines running without a thermostat is that they will run well below normal temperature. So if it's running hot with no thermostat then there is another problem. It could be as Kevin suggested, air in the system. Possibly the water pump could be bad. Did you by chance flush the system when you replace the radiator?

 

Hey, I replaced the lower sensor because the dash gauge was flat a zero after the overheat incident. The gauge worked after that.

I replaced the upper one, next to the thermostat housing, because it was still overheating after thermostat replacement so I thought maybe it was bad.

I’ve had the truck 8 years and have not replaced the water pump.

Thanks for the help!

 

Hey @73shark , I did not flush the system. Is burping it not sufficient to get air out? If I didn’t flush it, could there have been debris that caused a blockage in the new radiator?

thanks!

 

I’ll try flushing it this morning and see what happens.

 

Double check that your new lower sensor is correct. That one runs your guage, the upper one talks to the computer. My guess is the gauge is giving you a false reading.

 

Update:

I flushed it this morning with a garden hose fed into the upper radiator hose inlet, upper radiator hose disconnected.

The water ran clear pretty quickly, not much debris or sludge. I flushed with the engine running too.

Road tested, still running hot. Not in the red, but very close to it- 230-240 degrees.

Flushed again after the test drive. Same thing- water ran clear very quickly.

No visible leaks at the water pump. I’m flummoxed. Any idears?

 

It seems you tried everything, but overlooked a most important component, the water pump.

Not knowing the condition and past cooling system history it would be a good move to look over the water pump and while off just replace it.

Good practice includes when replacing any radiator, thermostat, water pump and belts and hoses. That is when all those parts are either off or easier to get to.
When the job is done there should be no problems ,,,,,,,,,,,,,,,,,,,,,unless poor quality parts were installed !
When possible, we always try to make sure the parts were made in the USA..
There is a lot of junk parts imported that are defective right out of the box.

 

Thanks! Yeah, sad about crappy out of the box parts being sold. We shouldn’t have to QC parts that are brand new.