98 12v
She runs great and never over heats just drivin around day today but if I have to drive a steap and long hill shell over heat pretty good 210 220 I'm not really sure why that is any one have any ideas or suggestions?

 

 

thermostat not opening entirely, or you've got some patching goo plugging up your radiator. or its a water pump.

you could try running that cooling system flush thru your truck and see if that helps. or drain and fill with straight water and that will tell you if your coolant is just worn out.

hope that helps

 

Get a new Cummins T-stat, nothing else

 

yea .. t stat .... if that dosent help .. possibly clutch on fan ...

 

you could check to see if the rad is clean it gets dirt and crap built up. blowing it off usually takes care of it.