2001 Ram

When I move the temp to cold cold air blows ok from floor vent but when I move it to the hottest setting the air is just warm. I checked the radiator fluid and it is up. Engine temp looks normal at about 190ish. Why is air not real hot? Is it the door in the duct not moving enough?? How do I check things??

Thanks

 

i have the same issue, my 98 has been like this ever since i bought it, on low fan speed, it has some what warm air, but as the fan speed increases, the temp drops. hopefully some one has a cure for this, its starting to get cold around here...

 

i cured mine by doing just this.

Replaced radiator, fan clutch, water pump, thermostat, and hoses.

Then the way i bled the system is make sure the front of the truck is higher than the rear. fill the radiator to the top, make sure heat is on full blast with the setting on defrost. Then when the thermostat opens add colant accordingly, and now my heats to hot, i always have it more towards the colder

 

My 99 V10 was blowing semi warm air last winter on low fan speed. It was barely enough to clear the windows and if turning the fan speed up it was colder. Just remembered I needed to back flush the heater core so 2wks ago, disconnected the line off the water pump and the heater return line going into the intake mani. Used the garden hose (full blast) and back flushed the heater core line so it came out the water pump side line. Then did the same from the water pump side and then back to the heater core side. Hooked it back up topped up the overflow. The temps coming from the vents is 10x better!
Back flush the heater core before you start replacing parts. If its partially clogged and you can dislodge it & you will get your proper heat range back

 

What Indy said, bottom line is, you have a heater core problem.

 

Thanks for the input.. So what could be clogging up my heater core?? The radiator has only glycol (green) and distilled water. I admit I have not changed it in like 5 years...

 

its typical wear and tear. youd be amazed on how many threads there are on heater cores

 

Well I was able to fix the issue.
Back flushed the core with hose. Drained radiator and put in hose water and bottle of peak radiator flush and ran it for a day. Next day drained everything and put in 50/50. Now it blows HOT.

 

Well, you need to change it!!! Antifreeze/Coolant deterioates just like gas or oil does. Just when Ethylne Glycol deterioates it becomes acidic.

 

hose water... if you live in an area with hard water/mineral deposits, hose water will create mineral deposits that will stop up the heater core and radiator.

use distilled water instead. there are 2 block drain plugs, one on each side behind the engine mounts. use those to get out all the tap water.