Water Pump/Thermostat Housing

Water Pump/Thermostat Housing







The water pump is combined with the thermostat housing and is bolted to the timing case lower section.

Caution during installation of the water pump: The impeller is made from reinforced plastic.

Leakage Restraint System in the Water Pump







The water pump has a leakage restraint system for the functional leakage from the pump shaft piston ring type seal. The coolant which escapes through the pump shaft sliding ring seal usually accumulates and evaporates through a hold in the leakage chamber (evaporation area).

If the sliding ring seal is faulty, the leakage chamber fills completely with coolant. Sliding ring seal leakages can be detected by monitoring the fluid level in the leakage chamber (inspection hole).


NOTE: In the past, fully functional water pumps were often replaced because the functional sliding ring seal leakage which is necessary for water pump operation resulted in evaporation residues being left on the external walls of the water pump.


The leakage restraint system has the advantage in that the coolant escaping from the sliding ring seal (normal, functional leakage) evaporates without a trace and cannot be mistakenly identified as a water pump defect during visual inspections.

Timing Chain Cover Lower Section




The waterpump mounts to the lower section to channel coolant to the engine block.