5.7 overheating under load only.

[Bimmerguy406]

Alright here’s the situation. I have a 2007 ram 2500 4x4 with a 5.7 hemi.
recently the engine temp gauge has started to run up over its normal spot in the middle when I go up over 3000 rpm. If I keep it under it’s fine. A local tuner recommended the fan clutch, which I knew was seized to the water pump from previously having to replace the wp gasket. So I threw a Hail Mary.
Replaced:
Water pump, Gates
Thermostat, slant 180
Upper and lower hoses
Flex a lite e fan conversion kit

I vacuum filled the truck and it gets hot anytime I am not at idle. But does get into the red. It will creep up as I drive well past the middle, and if I’m cruising it will start to come down, and if I stop it will rest at a little over halfway between cold and the middle. I already tested for combustion gas in the coolant, which turned up negative. The only thing left that could be culprit is the radiator, but before I pull the trigger I wanted to see if anyone else has experienced this and what their fix was.

 

[RamRod37]

the times I ran into issues like that wound up being a radiator stopped up one way to test is with both hoses off or loose from engine run water through top hose a garden hose turned on full should flow freely through radiator if you have to force water through top by holding your hand around the garden hose trying to seal between radiator and garden hose the radiator is stopped up

 

[jws123]

Like mentioned above once i have tried everything made sure no air in system in the end its always Someone used stop leak at some point and destroyed the rad or head gasket is leaking I have also gotten bad new tstats so not a bad idea to test it.

 

[RamRod37]

like jws123 said to that is another to check with engine cold pull of rad cap and start truck let it get up to operating temp watch for bubbles coming back into filler neck a good sign of head gasket if it bubbles

 

[Jim BB]

I would go with therasat ! lots of stats can go in both way it is poss it is in upside down or just a bad stat !
two choices pull stat put back together and see what happens if it still does it rad prob if it runs cool change stat and make sure it is in correctly and all air pockets are out!
Just a thought I have seen it many times where T stat is in upside down it happens they fit both ways

 

[Tominator223]

If rad’s not blocked & t-stat is correct position . Might be lean on fuel

 

[Bimmerguy406]

The jury is in: it was the radiator. For all posterior, if your truck is overheating under load ONLY start with a radiator.