1999 MC-12 C10 Aux Pump / overheating

[ustenor]

During the night, all is off and a noise comes from the engine bay. Checking in the morning finds the aux heat coolant pump making a racket. I disconnected it. Now leaking coolant and Now bus is overheating. Can't I run without the heater pump connected? Can I bypass it?

[freds]

Generally yes, normally there is a valve to turn off the heater circuit.

[luvrbus]

The booster pump or the circulation pump should not be running unless the system is asking for heat,I don't know how one or the other is causing the engine to overheat unless the coolant is very low from leaking look for valves ( ball or gate) on the engine and shut those and it should stop leaking 

Generally yes, normally there is a valve to turn off the heater circuit.