Grizzly 660 water pump breather leaking oul

[muckstuffer]

I recently completed my start of season oil change on my 05’ grizzly 660. The only thing I did differently than normal was to use a K&N oil filter instead of the genuine Yamaha one. After taking the bike for a short ride afterwards, I noticed a steady stream of oil leaking out of a small breather hose under the skid plate. I traced the line to the back of the water pump. I assumed this hose would leak coolant in the event of a water pump failure, but it seems to completely drain the crankcase. In looking at the exploded view of the water pump, I see there’s an o-ring where the pump mates to the engine. Could a failure of this o-ring cause this problem?

 

[Srxspec]

A failure of the o-ring would cause oil to come out of the water pump/engine case area, but not the water pump drain itself. Is there oil getting in your coolant? It sounds like the oil pump seal, on the engine oil side, is leaking oil into the water pump housing area.

 

[Srxspec]

 

[muckstuffer]

A failure of the o-ring would cause oil to come out of the water pump/engine case area, but not the water pump drain itself. Is there oil getting in your coolant? It sounds like the oil pump seal, on the engine oil side, is leaking oil into the water pump housing area.

There doesn’t appear to be oil in the coolant. Is the oil pump located on the same side as the water pump? The oil will drain out of the crankcase even when the bike is off. It’s a steady stream out of the water pump breather. I haven’t taken the water pump off yet before I was sure it’s the source of the problem. Could the aftermarket oil filter have caused a seal to blow? It’s the first time I used anything except genuine Yamaha.

 

[Srxspec]

It's the internal oil seal on the water pump shaft. Aftermarket oil shouldn't have had anything to do with it.

 

[muckstuffer]

Took off the pump and the oil seal was worn out. I also discovered that my crank case vent was twisted and probably not venting properly which may have contributed to the oil seal failure. It’s rebuilt and back together. Thanks a lot for your help.