Losing coolant from below the waterpump

[Wreckless]

Hi,
I just put in a new top end and while i was breaking it in water was dripping out of the hole on the case below the waterpump. When i stopped it would drip a little while longer, then stop. Once i started riding again it would continue to drip. After about 20 minutes of riding the water level went down a centimeter. It just started doing it after i did my top end. I am using distilled water and Redline Water Wetter. Do i need a new water pump seal? And how much do they go for?

 

[darringer]

Sounds like the water pump seal. Not very expensive. I think around $7-$8.

 

[Wreckless]

I just took the pump cover off and i don't see how the coolant can reach that hole. Its not even right under the pump cover, its towards the center of the case about an inch.

 

[va_yzrider]

There are two seals on the water pump shaft. You will need to pull the engine cover to get to the seals. The weep hole is between the two seals. This isn't a very difficult job, but make sure you inspect the impellar shaft to make sure it hasn't been scored (mine was ripped to shreds!). What happened is that the coating on the bearings broke free and chewed up the seals. Take a look at the microfische at www.yamahaoftroy.com and order the seals, bearing, and gaskets. This seems to be a pretty common problem with the YZ's.