2000 freightliner FL112 heater core location

Heater core and ac evaporator are sandwiched together in the hvac box under dash. The mickey mouse cable operated control valve on the top heater hose mounted on the firewall is the only factory water valve. It is operated by the ac temp control knob. They never fully stop hot water flow and always stick open. Best too put ball valve in its place that can fully close for ac to blow cold in summer and then just open up for heat in winter. The ac system in those wide mercedes based cabs suck. Blower motor has to run on high to get any cool air and heater is usually luke warm.

 

With new radiator and waterpump what is the engine water temp now. My 3126 Cat. will idle all day in 100-110 degree ambiant temp and never get above 140. The ac compressor runs even with heater on with that hvac system so evap and heat core are always mixing different air temps. A horrible system to get comfortable with.

 

Fan clutches on them things stay engaged all the time. Unless an air operated one was installed. The blades will turn all the time at engine speed. The clutch loosens up a little at lower temps but will always rotate blades. They rarely go bad. The way you tell is if they continue to rotate more then one time after engine is shutdown at temp. Then You know they are too loose.