Fresh water pump leaking

[MarkVon]

After noticing my coolant was low, I topped it up and then started the engine and looked at the fresh water pump and noticed it was leaking. Here’s a video of the leak:

https://youtu.be/BFfKTZYoUpg

I replaced the impeller and rubber ring a few months ago. Do you have suggestions for tackling this problem? Thx!

[MarkVon]

I just clamped off the two hoses connected to the pump and removed the cover. Cover seems fine. Rubber ring seems fine. There isn’t a gasket though...

I put a small amount of permatex gasket maker around inside edge of the plate and put it back on. I removed the clamps and it’s still dripping..

Here’s a video from underneath showing the leak and below is a wider picture:

https://youtu.be/cT2S3PpGIs8 (the sound is the bilge blower, not the engine)

The drip seems to be forming from further back on the pump, rather then the pump plate. Any thought/tips appreciated!

[edwardc]

It’s probably leaking from the “weep hole” on the underside, indicating that one of the seals is shot. A rebuild kit can fix that.

[MarkVon]

Thx Edward! Here’s a video from the reverse position, looking from the back of the pump:

https://youtu.be/tJe3F4vaC7I

Leak definitely seems to be coming from the ‘weeping hole’, rather then the cover. Given, I just changed the expeller and rubber ring, what parts of the rebuild kit do I really need?

[Peter]

Mark,

There are two rubber seals in the pump housing that are supposed to seal

1) the coolant side of the pump, and
2) the accessory drive side of the pump

You may want to pull the pump shaft and inspect it for wear - if it is badly worn replacing the seals will be for nought. You can get a new shaft but you may also wish to consider the MMI pump.

HTH,

Peter

[edwardc]

Originally Posted by MarkVon

Thx Edward! Here’s a video from the reverse position, looking from the back of the pump:

https://youtu.be/tJe3F4vaC7I

Leak definitely seems to be coming from the ‘weeping hole’, rather then the cover. Given, I just changed the expeller and rubber ring, what parts of the rebuild kit do I really need?

Shaft, seals, and bearings. In my experience, when the seal goes, the shaft gets worn, and a new seal won’t seal to it. Similarly, once water has gotten to the bearings, they will degrade and fail over time.

[capnward]

Yup, been there, done that. The pump leaked so much past both seals that despite the weep hole, water got into the accessory drive and into the crankcase. The back of the pump at the accessory drive looked like a vanilla shake had been poured into it. Oil on the dipstick was grey. I had neglected to notice the leaking pump, until the engine overheated because the pump was putting water into the bilge and crankcase as much as into the block. I had a Moyer rebuild kit ready to go, and the problem was fixed in a few hours. Shaft, seals and bearings were all replaced. One bearing wouldn't even turn. Then 3 oil changes were needed.
So deal with your leaking pump right away, and maybe you will only have to replace seals, instead of the shaft and bearings also. But it's likely you will need all new parts, as Edward says. Carry a complete rebuild kit. Best to have a spare pump as well. Rebuilding a water pump is not the kind of job you want to do while sailing.

[W2ET]

Hi, Mark:

Suggest you view the flange pump rebuild video to get an idea of what's what inside the pump.

Bill