ok so my truck takes generally about 5 minutes while idling plus about 25-30 minutes before it actually gets nice and decently warm. doesnt really blow just awesomely hot but its warm. ok but the problem is the 30 minutes it takes to heat up. ( dodge ram 1500 2001 model SLT)

 

I would honestly think its the thermostat, And being how cheep they are I would try that. but, What does your temp gauge show during this time? does it go up slowly? or go up normaly?

 

Check the coolant level in both the radiator and the overflow.

 

How long does it take for the temp gauge to tell you the engine is up to temp? And where does it top out at?