Water Pump - E46 M3
Part #: 11517838159 (11-51-7-838-159)
The E46 M3 does not suffer from the cooling nightmares of the previous E36 models. The original water pump uses a composite impeller, not plastic or metal, so the BMW pump will typically last 85,000+ miles before the bearings show signs of wear (the composite impeller is not the reason for preventative maintenance - it's the bearings). We prefer the OE BMW pump to the aftermarket brands because it uses the composite impeller, it has a proven reliability record, and the pricing represents a solid value upgrade. The pump is located on the front of the engine with the fan attached to it. The complexity of the S54 engine means the water pump has multiple gaskets and seals that should also be replaced. And if the thermostat has not been changed then this is the best time for a new one as well.
Composite vs Metal
BMW designed this water pump to use a composite impeller. It is much stronger than the plastic pieces that were so problematic in the mid-90s. The aftermarket solution to the plastic issues was to use a metal impeller. This solved the impeller issues but created some others. The metal impeller is heavier than composite or plastic and that led to quicker bearing failure on the E36 pump (sometimes within a year). The possibility exists that the same premature bearing failure can happen on the E46 M3 metal impeller pumps as well. The heavier weight also has the drawback of using more horsepower since it requires more effort to move the heavier piece. The composite materials solve all of these issues - light weight, strong, long lasting, and relatively inexpensive. They also come with a two-year warranty (most aftermarket pumps are one year). Original BMW water pumps for the E36 (and most other modern BMWs) now use a composite impeller so any issues with factory pumps are long gone. Original BMW water pumps for the E46 M3 are known to last over 100,000 miles and the composite is still in excellent condition (failure is usually typical leaks from worn bearings). For preventative maintenance we recommend a replacement around 85,000 miles.
This item fits the following BMWs:
2001-2006 E46 BMW M3
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Base Price: $379.95 (USD)
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