My truck is over heating and the temperature doesnt start to rise till I start driving it. I was told it could be the fan clutch or the thermostat. I was told how to check the fan clutch and its fine from what they tell me. I bought a new thermostat and put it in but its still overheating. I was told that you have to fill the radiatior first then fill the resivor with the remaining coolant. Does the radiatior create a suction with the fluid in the radiator to cause it to circulate? Or is the other possibility a bad raidator or a water pump thats about to fail? Im beating my head against the wall trying to figure this out.Thanks for all help.

 

I could be a water pump.
Have you checked to see if maybe you have air bubbles stuck in your coolant system?
does it just continue to climb or will it eventually cool down?

 

where did you get the thermostat from...get one from a Cummins dealership period...too many stories about how ones from autozone and NAPA dont work right

 

No I have no idea on how to check if there are bubbles in the system. It gets hot and stays hot. I schorched some stuff in my enginge compartment yesterday so its making me nervous. I called some guys and they said it could be my water pump because its not taking any of the coolant from the resivor. Yes I got a thermo from NAPA because the dealership wanted to charge me $73 for one. I will call cummins and see how much one costs.

 

the water pump doesnt circulate the coolant in the resevoir... as everything warms up it gets to a certain PSI... if it goes above the cap pressure it pushes it into the tank... as it cools there is an air valve that will actually allow the siphoning of the coolant in the tank back into the cooling system... check for bubbles isn't hard... run it w/o a raidator cap up to temperature and keep an eye for bubles once the thermostat opens... steady source of bubbles means a headgasket is leaking. if your getting it hot enough to scorch things under the hood... it probably wont be long before you do start seeing a steady strem of bubbles...

 

scorching stuff is bad have to belive it is the water pump. is there any dirt in the radiator from a dirt road or mud

 

I do live on a road with dirt and when it rains there is mud but I have a 5" lift and 35" tires and I dont drive very fast down the road so I dont splash it up under the truck. Also, since I have drained the fluid several times over the last couple days, I havent seen any mud or dirt on the radiator. Maybe I should just replace everything? Get a new water pump, head gasket, and whatever else I need to get it running again. Can someone give me a run down on everything I would need to replace all the parts that may be causing the problem??

 

Got it to stop overheating!! Thank goodness! It was the water pump. Thanks for all the insight.

 

a simple way to check out the thermostat and water pump is to remove the t-stat and run without it. without the stat, the engine will take a long time to warm up. if it still heats in a short time, check the bottom of the radiator and hose. if they are cold, the coolant isn't circulating. check the water pump by pulling it and looking to see if the impellor is intact or spinning on shaft.