R50 MINI Cooper (2002-06) R52 MINI Cooper Convertible (2005-08)
Apply some silicone grease to the water pump o-rings to help seal against the engine
Protects your engine against overheating
Replace thermostat, radiator hoses
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Check out some other sample projects from the book:
Directly below the alternator is the water pump. Begin removal by sliding back the hose clamps holding both the radiator hose and the small water hose on the rear of the pump. Now remove the water hoses from the pump. You may find that you need to walk the lines off the pump as they usually stick in place. The smaller hose may be a bit of a challenge to remove. If you are replacing all of the hoses, just cut it off with a knife.
It’s also recommended that you remove the two 10mm bolts holding the upper elbow piece to the engine block. Removing this elbow will also make removal of the pump a little easier. Be sure to also remove the small o-ring that seals the elbow to the engine block. You may see a little corrosion on the inside of the block with the elbow removed. If so, take some sandpaper and clean up the mating surface a bit.
Now remove the three remaining 13mm bolts holding the water pump to the block. Carefully remove the old pump from the engine compartment. Remove the flange piece from the top of the hose as we will re-use it with the new pump. Additionally, I recommend replacing the hose going from the pump to the flange (part number 11-51-7-829-913). It’s cheap enough insurance while you’re in there.
Now take the elbow piece and re-attach it to the engine block. Use a new O-ring (part number 11-11-1-487-596) in between the flange piece and the engine block.
Bolt the new pump to the engine block. For a non-S MINI Cooper, torque the bolts to 30Nm (22ft-lbs.); for the Cooper S, torque to 25Nm (18 ft/lbs). Now tighten the hose clamps holding the rubber connecting hose between the water pump and the elbow piece at the block. As before, you may want to replace the small section of rubber hose (part number 11-53-7-514-986) on the back of the water pump that connects it to the hard line leading to the thermostat housing. Now reconnect the radiator hose to the water pump.
At this point, you can retract the radiator service position, refit the wheels and fill/bleed the cooling system (please refer to our article on thermostat replacement for more info).
In this picture, you can see the lower 10mm alternator bolt that also secures the water pump to the engine block (green arrow). You’ll also need to loosen the hose clamps on both the lower radiator hose (purple arrow) and also the hose to the heater core (yellow arrows).
Remove the two 10mm bolts holding the water pump flange to the engine block (purple arrows), then remove the three 13mm bolts holding the water pump to the engine block (green arrows). Once free, remove the lower radiator hose and heater hose from the old pump. Removing the pump with the upper water pump flange still attached is much easier then trying to remove the hose in-situ. Once the pump is removed, remove the old hoses from the flanges. Also peel the old O-ring out of the water pump flange.
Here you can see the evidence of a failing pump (green arrow). This buildup coming out of the lower weep hole on the backside of the water pump indicates a leaking shaft seal. Once you see this, the pump must be replaced.
Here’s a close-up of the inside of the water pump once disassembled. In this picture you can see how coolant has been leaking from the shaft seal (green arrow), pooling up in the cavity below, eventually draining out the weep hole (purple arrow). Normally, the weep hole should look like the one on top (yellow arrow). Only a matter of time before this pump would have failed altogether.
It’s a good idea to clean the mating surface of the water pump flange with some sandpaper if there is any buildup of corrosion or rust. Just make sure you wrap the sandpaper around a straight edge and sand it flat. Do the same for the engine block as well.
Fit the new water pump flange hose to the water pump. Note the angle of the hose. It helps to pop the water pump flange into the top of the hose and test fit the connections with the pump mocked up in place on the engine block. Don’t forget to also install the lower hose clamp.
Now re-fit the water pump back on the engine block and reconnect the heater hose on the right side. As you can see here, the water pump flange does not quite line up with the threaded holes on the engine block. Keep the upper hose clamp loose so you can turn both the hose and also the flange until it does line up. Once it does, re-install the two 10mm bolts and slide the hose clamp up into place.
Applies to: R50 MINI Cooper (2002-06) - R53 MINI Cooper S (2002-06) - R52 MINI Cooper Convertible (2005-08) - R52 MINI Cooper S Convertible (2005-08) - R52 MINI Cooper S Convertible (2005-08) - R56 MINI Cooper (2007-) - R57 MINI Cooper Convertible (2007-)