Cool heat

[Tharrison365]

My 99 5.9 is not making a lot of heat in the cab. To me the temps are running a little cooler but not positive. The fan also kicks on as soon as I start the truck no matter the temp. I am thinking it is a thermostat stuck open but not positive. Looking for ideas. This is the normal operating temp for the truck. I have had it for about 2 months now and as its getting cooler I want the heat back.

 

[dapepper9]

Should have plenty of heat at that temp.

Start simple. Check the coolant level. Turn fan power level down to the minimum and switch the temp switch from cold to hot and back a couple times. Listen for movement of the doors in the dash. Do the same thing with the vent switch. Sometimes the blend doors and such get sticky and don't like to move do what little resistance the air blowing provides is enough to keep em from moving. Might need exercised a little.

If doing these things doesn't help you can try back flushing the heater core.

Edit: also unless you have an aftermarket electric fan, the coming fan will pull air regardless of temp as it's motor driven

 

[crazy_luck]

All of the 5.9 trucks I've had ran a little warmer than that, closer to the 210 mark, with the last one I had being the exception because I put a 180° thermostat in it. And I regretted the 180° thermostat when winter rolled around because I had poor heat. After swapping the standard thermo back in, heat was better but not as warm as the previous truck. Turned out to be a plugged heater core.

 

[New2dodge89]

I'm havin the same issue, I was thankn possible thermostat issue, last winter mine over heated one time and after that it started runnin at a higher temp and the heater was amazin. I figured my thermostat was stuck and had fixed itself but now that it's gettin cold outside again the issue is comin up again.