Cabin heater not getting hot

[crazy jerry]

for anyone not sure how a heater core works. if both hoses are hot then hot water is going through it. simple as that. regardless of hose orientation

 

[Ozymandias]

No it isn't....

 

[gsbrockman]

I had a friend with a 2016 3500 (very high miles) had a heater core issue. Both hoses seemed to be about the same temperature, but the flow through the core was restricted and somewhat slow. In his instance, a new heater core fixed the problem.

 

[crazy jerry]

I had a friend with a 2016 3500 (very high miles) had a heater core issue. Both hoses seemed to be about the same temperature, but the flow through the core was restricted and somewhat slow. In his instance, a new heater core fixed the problem.

in older vehicles they can develop corrosion buildup in the tubes. which reduces flow and hinders heat transfer from the hot water to the air blowing across the tubes. heater core is nothing but a simple heat exchanger (aka radiator)

 

[brucejohnson]

Craig,
Which HVAC do you have, manual or dual zone/automatic?
I seem to remember some vehicles had calibration issues with the blend and other doors in the HVAC system. There was a manual and a dealer calibration available. Anyone remember seeing or experiencing such events? Then there is the bad actuator or broken doors...actuator or heatertreater time?

 

[JR]

Craig,
Which HVAC do you have, manual or dual zone/automatic?
I seem to remember some vehicles had calibration issues with the blend and other doors in the HVAC system. There was a manual and a dealer calibration available. Anyone remember seeing or experiencing such events? Then there is the bad actuator or broken doors...actuator or heatertreater time?

I've seen the HVAC system need to be recalibrated on a new silvarado as a result of a depleted battery. Good call.

 

[firefighter_2000]

Reverse your heater hoses on the core, you may have an air block. The hot/supply goes into the bottom of the heater core.

Update: Finally switched the hoses around yesterday. Had heat immediately. They’re a pain in the ass to get to, but it worked!
Thanks Hoefler!!

 

[Cummins12V98]

How did they get reversed?

 

[firefighter_2000]

How did they get reversed?

Had a delete done last year.

 

[Tmartin000]

Its threads like this that makes Forums like this 100% worth the minutes you spend reading, laughing, and sometimes wincing.

Great job guys!

 

[Hoefler]

Update: Finally switched the hoses around yesterday. Had heat immediately. They’re a pain in the ass to get to, but it worked!
Thanks Hoefler!!

Sometimes the simplest things are not so obvious. Glad to be of help.