I have a heat output issue. Not very much heat at all. Here are my temp readings:


Heater set at 90d
Coolant temp 198d per DIC gauge right in the middle
upper rad hose 188d
lower hose 167d
heater hose 208d (not sure which is inlet or outlet)
heater hose 270d
drivers dash vent 83d
passenger vent 87d

Inside temps were taken with a good cooking thermometer. Engine temps with a laser infared temp gun. The heater hose at 270d surprised me how high it is. New OEM AC 195d thermostat installed yesterday. Is this a plugged heater core?




Pat Callaghan

Did you say 270d for a heater hose?

yep. checked it twice.

One thing I just thought of. I had just driven a 20 mile ride home. Maybe I was reading heat that was radiating of the exhaust onto the heater hose.

Check the temp of BOTH HEATER CORE HOSES..... if nearly the same the core is not the problem, sounds like a temp actuator.......

If one hose is much hotter than the other, then the core is plugged.....

Is this a dual temp system?

I am going to recheck tomorrow but I am going to take the reading a bit further from the firewall. probably where the hose comes out of the tensioner. It is the automatic system with separate adjustment on the passenger door.

Are the mode and inlet actuators working?

Problems in the HVAC should set "B" codes.....not all scanners read B codes.....

I hear movement but have to get under there to see. I work until Sunday so will have to wait until then. No flashing of the climate control panel. My scanner does not read anything but powetrain codes.