Hi all,

I had recently had my MC21 engine fully re-built.

I had the mechanical water pump seal (19217-KV3-831) replaced as a precautionary measure during the rebuild.

Once the engine was re-installed and running, it leaked coolant from the inspection hole on the RH side of the casing - a single drop every few blips of the throttle - which i know points to a faulty/damaged seal.

I removed the casing and impeller shaft and realised there was some corrosion on the impeller shaft - not loads, but enough that it needed to be rubbed down with some fine wet and dry to be totally smooth.

When i re-installed the impeller and ran it, it leaked again, as bad if not worse.

I spoke to the guy that built the engine and he said the seals can need to 'bed in' after some miles of use.

I am not sure i agree? Has anyone had any experience of this seal leaking when installed and whether they need to bed in, or settle in any way after multiple heat cycles or a few proper miles?

Personally i suspect the small amount of corrosion has damaged the seal, but before i bin it and buy a new one and strip it down again etc, i wanted to ask if anyone had any thoughts/experiences?

Any ideas very much appreciated.

Thanks,
Max