BMW Water Pump and Thermostat Kit - 11517838201KT

A complete water pump and thermostat kit for servicing your E9X M3's cooling system, includes all seals, hardware, and pieces for a complete job

This water pump and thermostat kit includes everything you will need in order to complete a service. The water pump and the thermostat play a critical roll in controlling engine temperatures.

The thermostat controls the flow of coolant through the engine and either closes or opens at a default temperature. In the S65B40's case the stock thermostat opens at 79° C with the goal of maintaining this operating temperature under all conditions. The thermostat will fail with age usually in the open position which will allow coolant to constantly bypass through the housing preventing the engine from reaching operating temperature.

The water pump on the other hand pressurizes the system and allows for coolant to flow throughout the engine, radiator, and associated cooling system hoses. The water pump will fail due to age most commonly seen as a coolant leak through the weep hole. This indicates that coolant is making it past the impeller shaft bearing. In extreme cases the impeller can disconnect from the shaft or break which will prevent the coolant from circulating through the engine which will cause an overheat condition.

In this kit FCP Euro includes an OE quality German made water pump with a metal impeller and an OE Wahler thermostat. Along with these components we also include replacement upper and lower radiator hoses. You will want to replace these to avoid coolant leaks via the quick connect couplings due to failed o-rings inside. Sometimes you can get away with reusing these hoses but there will be no better time to replace them. In order to remove the thermostat housing you will need to remove the fuel rail with the injectors attached so we have also included fuel injector o-rings. We have also includes all required replacement o-rings, hardware, and clamps needed per BMW TIS recommendations during this service.

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