Heater Hose: Description and Operation

Heater feed and return hoses

Heater System Components - XK Series:

Heater System Components - XJ Series:

Clamp Identification:

NOTE: * These hoses are flattened at the bends by design and NOT by incorrect installation.

The heater feed and return hoses are connected to the engine feed and return hoses by 'Quick-Fit' connection unions. The feed hose has a Norma R20 connector and the return hose a Norma push and seal connector. The coolant system bleed joints have Cobra clamps. All remaining hose connections have spring band hose clamps.

The engine feed hose is connected to the engine bypass housing and the engine return hose is connected to the engine water pump.

Non return valves
The heater bypass hose has a non-return valve, located between the engine feed and return hoses. The valve prevents the water pump from recirculating coolant from the heater at low engine speeds. The flow indicator arrow embossed on the valve body MUST point towards the coolant header tank.

CAUTION: Coolant flow will be compromised if either valve is fitted incorrectly. Observe the correct direction.

A second non-return valve is located in the heater outlet to water valve hose. This valve prevents hot coolant from flowing into the heater with the engine switched off. The flow indicator arrow MUST point towards the water valve.