anythoughts about what might be causing this truck to overheat. Only seems to do it when pulling with a trailer or in stop and go traffic with trailer. replaced the thermostat and replaced coolant. stiil running warm. dont know where to turn and in what order. any advise is very much appreciated. Thanks in advance.

 

is any body there

 

WELL, first off welcome to DTR, second we drive cummins around here. And as for your problem I would say that your rad is stopped up from your puke bottle running over and collecting dirt on it.

 

Sounds like new radiator time and maybe new fan clutch if its not pulling any air through radiator. Did you hear fan clutch come on? Did you look into radiator fill hole when you had the coolant drained? Most likely plugged up radiator.

 

fan clutch

 

Spray all the bugs off the radiator and then I'd check the fan clutch. I had to replace my fan clutch a few years ago but still have the stock radiator.

If that checks out then try a radiaor flush and then it's time to recore the rad or get a new one. Or the rad cap could be bad but then it would always overheat so the caps not likely.

Of course its possible the water pump is bad. Get a mirror and check the weep hole on it for a rusty water trail. The weep hole is hard to see since its under the pully wheel of the water pump. They are pretty easy to replace. I'd get it from Cummins if you can my last NAPA pump lasted 3 years. Next one is comming from Cummins.

Check out the viscous Fan Clutch. I think if the engine is cold the fan clutch will free spin but if its hot it should be stiffer.

 

X2 on the puke bottle contaminating the outside of the rad. Its hard to see but you won't believe how bad it can get. Just wash it down with varsol/solvent and blow dry.

 

Mine would overheat too just pulling an empty trailer. Cleaned the radiator fins and now the temp never changes. It doesn't take much to plug the cooling fins from the puke bottle.

 

I thiught my rad was clean till I pulled it out of trk and really washed it . WOW. There can be so much dirt on the back side ..................

 

X 2 on the cleaning with soap, degreaser, or something and high pressure wash. Fan clutch too, 2nd. I had the same problem and someone pointed out the radiator, helped a lot. Search fan clutch test I believe if the cleaning doesn't do it.

 

Check the puke bottle first, it might be the quickest, cheapest fix. Here are my before and after pics.