Coolant Leak from Water Pump Mounting Flange on Mini W11 Engines - Engine Builder Magazine
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Coolant Leak from Water Pump Mounting Flange on Mini W11 Engines


There have been complaints of a  coolant leak from water pump mounting flange on some Mini Cooper R53s with W11 engines.

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The connection between the water pump housing and the mounting flange on the crankcase is leaking. The rubber O-ring may have been crushed on one side by incorrect centering of water pump to mounting flange.


1. In case of customer complaint replace the two O-rings, part number 11 51 7 509 186

2. Apply "Syntheso Glep 1" to the O-rings, part number 83 23 9 407 778.

3. The following alignment procedure should be done in sequence:

a. align water pump to supercharger and tighten (refer to service manual for torque specifications).

b. align water pump to mounting flange and tighten flange.

c. align supercharger to mounts and tighten.

4. In case of coolant leak caused by water pump/flange misalignment, it is not necessary to replace water pump.

Some or all of this information was provided by the Automotive
Parts Remanufacturers Association (APRA). For more information on
technical bulletins available through APRA call 703-968-2772 or visit  

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