Persistent Water Pump Oil Leak-Help!

[Kurt]

I posted a little info about my issue in an earlier post. I have a less than 6 month old Oberdorfer 202M7 water pump that started oozing oil from the weep hole about 2 days after I bought this boat (water pump was just installed). So, I recently bought the rebuild kit here and replaced the outer seal. Started the motor up and there was no leak for about 10 minutes at 1500 RPM - then, it started oozing oil again from the bottom of the weep hole. You can look in the top of the weep hole and actually see oil all around the seal. The seal was installed correctly then and now, just seems to fail prematurely. So, what now? Is it possible that the cam on the motor itself wobbles? Maybe this pump is a lemon? My two thoughts are to just replace everything in the new pump since I have the rebuild kit, even though the shaft, pump body, etc. all look brand new. If that doesn't work, I've wasted money and time and I was thinking of just scrapping the whole thing and buying the different designed Moyer packless bearing pump. Still wonder why this persistent oil leak could be happening.

[jayw]

Is the shaft of the pump damaged or rough where the seal seats? Or maybe the body of the pump is damaged somehow. A rough shaft will chew up seals quickly.

[tenders]

1. Are you sure you installed the seal with

• the words stamped in the seal facing away from the engine (the words on the seal closest to the impeller face towards the engine, the words on the seal closest to the engine face away from the engine so the words on the two seals face each other)
• flush with the face of the pump flange (ie, not countersunk)
• level with the face of the pump flange

(sounds like you're pretty sure you did)

2. Are you sure the pump shaft has not been scored at the seal?

3. Are you sure the impeller retaining clip is installed so the shaft doesn't wobble fore and aft?

If "yes" to all three then the only things left I can think of is that the shaft is bent (and oil is leaking around the rubber seal as it flops around) or that the area of the pump around where the seal is pressed is badly nicked (and the oil is leaking between the brass shell of the seal and the bronze pump body, OR the seal can't really be installed flush and level). The first is fixable with the new shaft you may have. The second MIGHT be fixable with a Dremel tool.

[Don Moyer]

Kurt,

If you bought your Oberdorfer 202M-7 from us, please give me a call at (410)
810-8920 as they are warranted for one year.

Don

[Kurt]

Thanks for the advice everyone. Don, unfortunately I don't know where the pump was purchased. I saw the old one installed on the boat right before I bought it and had the owner buy and install a new one because the old one was leaking water badly. At this point, I guess I'll replace the shaft and the outer seal again as I have spares for both from the rebuild kit. The shaft can't be wobbling too much or else I would imagine both seals would fail and I am only having problems with the outer oil seal. The seals are installed in the correct orientation. I'll let you all know if I end up having success or not with this 'new pump rebuild'.

Thanks again.

[Kurt]

So, for those who become stumped with a leaky water pump like I was, here is the follow up and way I finally resolved the situation. So, to summarize, my 6 month Oberdorfer was seeping oil from the weep hole at the bottom of the pump. So, I replaced the oil (outer) seal. No improvement. I then rebuilt the entire pump - new seals, new impeller, new shaft. No improvement. Gave up as there was nothing else I could do with this pump. Purchased the Moyer flexible impeller pump as I thought maybe the packless ball bearing arrangement would be more robust. Installed that and have put about 3 hours on the motor and, guess what, no more oil leakage! So, I have no idea what the issue was. Maybe that Oberdorfer was a lemon or something. Another interesting tidbit is that the water is pretty warm right now in San Diego and my raw water cooled engine (that is very well maintained and has been pressure and acid flushed recently) was running at 180 degrees under load with the Oberdorfer pump. With the Moyer designed pump it is now running at a consistent 170 degrees under load at 2000 rpm - a full 10 degree improvement in temperature! So, hopefully this experience helps anyone considering replacing their water pump or having similar problems.

[cat30]

retaining clip

it was my understanding that the retaining clip isn't required for anything except to keep all the parts together until the pump is installed? there isn't any wobble without the clip?

[tenders]

I could be wrong but I think there is a bit of fore-and-aft play without the clip. The impeller fits pretty tightly into the chamber fore-and-aft and the clip anchors the shaft to that fairly tight specification.

I don't see how it would be possible to cut the slot on the engine side of the shaft to match every engine to perfect tolerance, which makes me suspect those slots are cut a little deeper than necessary. Over time (or maybe over not so much time...?) without the clip the resulting wobble can wear the inside of the cover plate and/or cause the seals to leak.