No dashboard heat - 2004 Friendship G7 Freightliner

[boatguypat]

I have an issue with the dashboard heat on my 2004 Friendship G7 (Freightliner) with the Cummins engine. It blows cool air - never seems to warm up, although the engine is at the correct temperature. I removed the hose from the small heat exchanger in the front, and found a very small amount of antifreeze moving through the system. I suspect that is the problem, not enough fluid to heat up the exchanger. Does anyone know, is there an impeller or separate pump somewhere that circulates the engine coolant to the heat exchanger? Or does it simply work off the engine water pump? Could it just be a collapsed/kinked heater hose? Or does the dashboard heat not work well because of the distance?

[Sundancer268]

Probably your control valve in the water line, some of the Evans Tempcon valves have been known to fail and provide no heat or to much heat and the A/C can't keep up, especially when the factory installed the backwards. The heater is supplied by the engine cooling pump, there is no separate pump. I had some massive air leaks under the dash so that the heater could not keep up and I froze. I found the leaks when I had the dash apart to replace the TXV on the Heater/A/C box. I am betting a failed control valve.

[boatguypat]

thanks - i will check that and report back

[THenne1713]

While problem (might be) a control valve problem, it is also a common symptom of low water in radiator system, usually starts w/ small leak at the water pump but only when engine running.

[boatguypat]

Thank you.