Thanks for all the advice. It wasn't that cold when it was leaking and it was a steady flow when the engine was running. The pump also squealed periodically so I need to do it. However, the "bizzare' part that someone mentioned is what concerns me. The pump is not like the pump on the 617 I have here in the US. There is no flat plate at the front with bolt holes on it. There is just a large bolt hole in the middle of the pump shaft to which the fan and pulley attach. You have to run a pin through the shaft at the motor end of the pump (through large weep holes essentially) because otherwise the whole pump shaft will turn when you attempt to tighten the fan and pulley. I'm assuming that this large center bolt is quite a bit bigger than 10mm since it holds everthing together on the front of the pump.