2000 ram slt mild heat

well i just bought a ram......temp dropped and noticed that there wasent much heat..... been through 2 195deg thermostats in 2 weeks,flushed the core, checked the blend motor(removed motor and acctuated door by hand), and then noticed that it gets hoter air by reving the engine.... all the controlls work good so that should count out a vaccume leak right???? could a "going bad" water pump not be pumping enough coolant to the core??? i also noticed that right when i switch from cold to hot it is hot air then about 2 sec later it is just mild until i revv the engine.... if i drive the truck for 10 min or so it stays just mild never gets too hot to turn down and its only 40 deg or so...also engine temo is right around 190 or so just below halfway and steady not fluctuating....please help i have no idea what to check next.... also anyone have experiance changing or pointers on the water pump replacement..???
thx

Weare experiencing the same problem with one. Ours has a v-10. I havent found the answer but appreciate it if you get any insight. I will do the same. My truck is coming back next week to adress the issue (again). Perhaps we are using the wrong thermostats and the bypass feature isnt working properly?
One last note: We have seen earlier model Caravens withg the 3.3 engine do the same thing with healthy water pumps and never did find a solution. Water pump speed may be a factor and maybe part of this is the nature of the design. just a thought.
HeadacheGuy
Wzrd007@aol.com

air lock in the cooling system will cause this. Do you hear coolant go through ur heater core when you hold the engine at rpms higher than idle? the sound would be heard on the passenger side dash.