My 1998.5 cummins overheats when I pull my camper that weighs about 10,000lbs.I changed the thermostat, and water pump and it still did it. Yesterday I had a new raditator installed and it still ran a little hot even without the camper, around (210 degrees). When I'm on the highway around 70mph and it gets hot i can take the overdrive off and it cools back down real quick to around 220-230. Does anyone have any ideas what else may be going on. I'm leaving for the beach on Friday and would like to figure this before hand. I really don't want to drive 300 miles without overdrive at $4.75 a gallon. HaHa....

Thanks
Chris

 

check your fan clutch

 

How will I know if the clutch is broke orworking?

Thanks

 

Stick yer finger in it.

May look for an aux oil and aux tranny cooler, 200-400 a piece.

 

It already has an oversized tranny cooler. Don't think tranny colloer should effect engine temp though. Anything else??

 

Did you put the right stat in? You'll want a 180 for a 2nd gen. If you're confident that you've done that, then the next logical thing would be the fan clutch since you've already replaced everything else. I was going to suggest a dirty radiator, but since youreplaced that - that's out

How about everything else? Have you cleaned the outside fins of your innercooler, trans cooler, etc? If they're restricting airflow, it aint gonna get to the rad no matter how new it is.

 

I think NAPA gave me a 190-195 degree thermostat. They said that's what came in the truck. I pretty sure everything around the rad is clean.

Thanks

 

I'm pretty sure a 180 is what came stock. Hopefully Parts / service will chime in for us

 

190 degree is the correct thermostat. It is more than likely your fan clutch not engageing. Here is the way that I know to test the fan clutch.

If the fan assembly free-wheels without drag (the fan blades will revolve more than five turns when spun by hand), replace the fan drive. This spin test must be performed when the engine cool

 

refloyd is correct on both