I have a Ram 3500 with the HO 6 speed 144,000 miles and when it is pulling through the hills or in the mountains it wants to get hot. I replaced the clutch fan but that did not seem to help. It is not cool to be pulling the hills and have the guage wanting to red line. Any thought on where to look next for the problem? I have the local dealership scratching their heads.

 

Get a large transmission cooler. This will help a lot.

 

Let's see. Water pump, radiator, thermostat, hoses, fluid condition, etc. Have you tried the tow cool or similar products? I don't know if or how well they work, but perhaps something to look forward too. I would look at the condition of hoses and thermostat. If no pressure is being held, 16 psi I think, then the boiling temp goes down.

 

First, you need to be sure the truck is actually overheating and the gauge or sender are not at fault. As you describe the situation, this is probably not the case, but it pays to be sure. I've seen people go nuts trying to fix nonextistent overheating problems. Bad ground connectors can contribute to this.

All the sources noted by others can be problems. I've seen thermostats that were not opening completely (easy to test in a pan of water on the stove with a cooking thermometer). I've seen water-pump impellers slipping on the shaft, especially stamped-steel ones.

Are you sure the system is clean and clear? Have you flushed? Have you had the radiator tested?

Just some further thoughts.

All the best.

 

If it were mine I would flush, refill with new antifreeze, and change the thermostat while at it (they are cheap). Old or an improper mix of antifreeze will make a vehicle overheat.