Truck runs HOT unless heater is on HELP!

[KansasRam1997]

Everything is new radiator, hoses, thermostat etc. Only the water pump is the original that came with the truck... NO leaks, coolant level is good.

The truck runs HOT getting up to 250 degrees unless I keep my temperature dial to the max heat setting, even then it will stay around 205-215 degrees. I already tried burping the air out for about an hour using a Lisle Spill Free Funnel. I don't know if I need to burp the air some more, or buy a thermostat that requires lower heat to open.

Let me know of any advice ya'll can think of,

Thanks!

 

[Dubstep Shep]

First, use a vacuum filler. That's the only way to make sure there's no air in the system.

If that doesn't fix it, I'd say you probably should start looking in the motor and at the head gasket...

 

[dapepper9]

I would also do another tstat. Very very common for them to be bad out of the box. Considering the low price of a new stat and the fact that it's really not that hard to replace I would definitely look that direction. Stant seems to be a fairly reliable brand.

Also highly possible the pump is going and not circulating it well. Take the belt off and see if you can move the fan up and down. If there's any play replace it.

 

[bassslayer25]

+1 for a new water pump. Mine went out while I was on vacation. On the way there i was pulling our camper and my temp was around 210. Didnt think anything of it. Driving around the camp ground it went out. Replaced it. So pulling the camper on the way back it stayed a 180 the whole trip. Took another 3 hour trip recently pulling the camper and it hovered around 180 the entire time as well. So I vote water pump.