Insufficient Rear Unit Heating

1. Check operation of the water valve controlling flow to the rear unit. Be sure it is fully open when the control is in the “FULL OPEN” position. Allow 15 minutes of engine operation with the water valve open, the hoses going from the valve to the rear unit should be very hot and the return hose to the engine will be hot to the touch but at a lesser degree.

If air gets into the coolant system, an air pocket can occur in the rear heater coil stopping the flow of water.

To purge: 1) Get the engine up to operating temperature and turn on rear unit.

2) Using duckbill clamps, pinch off the hose feeding the front heater between the “Y” or “TEE” and the heater coil. This will send the total pressure of the water to the rear unit, which will force the air out of the rear unit. Continue to run the engine for 3 to 5 minutes.

If these conditions do not exist, there is a restriction somewhere in the system, which might be corrected. In extremely cold climates it might be advisable to insulate the water hoses to the rear unit. If there appears to be an air output problem see step 7 in the Insufficient Rear Unit Cooling section.