So i have a 91 cummins that has recently started over heating i replaced the t stat and the water pump and it seems to be fine when idling but as soon as i drove it the temp goes right up to hot so i felt the rad hoses the bottom one is warmer then the top but by no means are they hot and at the same time i started over heating my heater quit on me any help would be appreciated i really dont know where to go from here

 

I take it you replaced the T stat and pump after it started to heat up.
With the bottom hose being hotter sounds like the thermostat is not opening.
Was anything done to it before the heating started?

 

Any progress?