Auxiliary Cabin Heater: Description and Operation
HEATER-DIESEL ENGINE COOLANTDESCRIPTION
The 2.8L diesel engine uses a supplemental engine coolant heater (1) to help heat the engine coolant prior to it entering the heater core (4). This mechanical device is commonly called a viscous heater. The supplemental engine coolant heater is driven by the engine accessory drive belt (3) and has an electromechanical clutch (2) which is controlled by the engine control module (ECM).
OPERATION
The supplemental diesel engine coolant heater (viscous heater) uses an electro-mechanical clutch that receives a signal from the diesel engine control module (ECM) via the A/C-heater control and the viscous heater controller, to energize and engage the clutch. Once engaged, the clutch allows the viscous heater to increase the temperature of the engine coolant flowing to the heater core to provide heat to the passenger compartment quicker than diesel engines without the viscous heater.
The viscous heater uses friction to heat a special silicon oil within its housing. The generated heat is then transferred to the engine coolant when the coolant passes over the fins within the housing. When demand for passenger compartment heat decreases the viscous heater receives an input from the heater controller to disengage the clutch.
The supplemental diesel engine coolant heater cannot be repaired and, if faulty or damaged, the entire heater assembly must be replaced.