2021 6.4 2500 heat issue

[Jdn03]

I apologize in advanced as this will be long winded. I have a 2021 tradesman 2500 with the 6.4 hemi. 55,000 miles in it. On a road trip home from traveling out of state for work I had a tensioner pulley fail and the belt fell, the engine over heated and blew off the pressure in the coolant system. I stopped the vehicle, replaced the tensioner pulley, topped off my coolant system but have since been having issues with the heat. Specifically on the driver side. Heat works fine on passenger side but Luke warm at best on drivers side even at higher RPM. I had a guess that it was air bound. Took it to a dealer and they said they bled a lot of air out of the system and it was good to go. Upon picking the truck back up I noticed that the heat in the driver side works, but only at higher RPM. At and idle I’m still getting cool air. Any ideas as to what the issue is? Did the dealer fail to completely bleed the system? I plan on returning the vehicle to the dealer but I’ve been scratching my head on this issue since before Christmas.

 

[dieselscout80]

I apologize in advanced as this will be long winded. I have a 2021 tradesman 2500 with the 6.4 hemi. 55,000 miles in it. On a road trip home from traveling out of state for work I had a tensioner pulley fail and the belt fell, the engine over heated and blew off the pressure in the coolant system. I stopped the vehicle, replaced the tensioner pulley, topped off my coolant system but have since been having issues with the heat. Specifically on the driver side. Heat works fine on passenger side but Luke warm at best on drivers side even at higher RPM. I had a guess that it was air bound. Took it to a dealer and they said they bled a lot of air out of the system and it was good to go. Upon picking the truck back up I noticed that the heat in the driver side works, but only at higher RPM. At and idle I’m still getting cool air. Any ideas as to what the issue is? Did the dealer fail to completely bleed the system? I plan on returning the vehicle to the dealer but I’ve been scratching my head on this issue since before Christmas.

Likely a plugged heater core.

Try flushing it with a power flusher tool.

There are many instances of this happening and flushing it helps.

That said if not the heater core will need to be replaced. This means the whole dash has to be disassembled.

Ps you posted this in the 4 gen sub forum and you have a 4.5 gen truck.