oil coming out of waterpump weep hole...?

Guys...I have an '01 WR426 that has recently developed an oil leak. I finally traced it back to the weep hole below the waterpump. She is seeping a small amount of engine oil. Now...I've heard of coolant leaking out of this hole to indicate a worn seal. But oil? I've never heard of that. Both oil and coolant are clean, no cross contamination. Bike runs great otherwise.

Any ideas?

Thanks in advance...


Did you over fill it with oil?

It's the same scenario as coolant coming out of there but instead it is the oil seal on the other side. There is 2 seals face to face, 1 for oil, one for coolant. Replace both seals, the impeller shaft and bearing. It's a cheap fix, maybe $30 in parts.

I might be a bit overfilled on oil....would it come out of there of it were overfilled?

No, tribalbc is correct (except the seals are more accurately "back to back"). The oil seal has failed.

It is unlikely this is related to any looseness in the balancer shaft bearings, but it never hurts to check. Ordinarily, such a problem would manifest itself as a coolant leak before oil showed up.

Replace both seals while you're in.

ok...so what's the best way to go about this job? This is my first thumper.... Also....what parts would I need?

Download a manual to start with:


You'll need to drain the coolant and the oil. The clutch cover can stay on the crankcase cover, although the top two bolts run all the way through to the crankcase, so they have to be removed. Remove the right side crankcase cover, hold the impeller shaft by the flats ground on the fat part near the bearing (13mm) and unscrew the impeller (tight, but a standard right hand thread: counterclockwise to loosen).

Note the seals. The larger, spring loaded sealing lips face up, out of their pockets, toward the fluid they control. This makes them look backward, but they belong that way. Check the shaft for grooves worn in by the seals, and also check the balancer bearing for excess clearance.

Normal parts would be both seals, a crankcase cover gasket, the shaft bearing, and possibly the shaft.

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