help. '02. Yz250,

Photos will help your cause

Do you mean by the rubber gasket above the water pump? The rubber pawervalve cover gasket?

If oil is getting there, then the #6 seal is bad. But I will guess that isn't the only thing worn out. If you are getting coolant in the gearbox oil, then the seal #4 is bad too.

Might be a good ideal to replace both seals, bearing and impeller shaft. If you are on a budget, try just the seals. If it begins to leak in a few rides, you know the bearing and shaft were worn too.

If bearing is worn, the shaft will wobble. The shaft will have a groove worn in where the seal touches. I'd replace all the parts so you don't have to do it again later.

It's damn near impossible on the double seal setups for water or oil to pass both seals and get to the other side. There is a weep hole between the 2 seals which will allow any liquid to drip out first before it gets to the second seal. Look underneath and make sure the weep hole isn't clogged with dirt. Poke it open. I think the oil might actually be coming from that weep hole and you think it's coming from the gasket. At the end of the day, the solution is still the same - completely rebuild the pump with seals, bearing, shaft, and gaskets.

Back up, folks.

The YZ250 has a powervalve cover that turns through 2 dimensions (front and side of the bike.) It is located just above the water pump, and is sealed by a rubber gasket and cork gasket combo which is janky at best. I'd be willing to bet you have some combustion sludge which is leaking out from your powervalve down to the water pump cover gasket. Take a close look.