Yet another water pump thread.

Yeah, mine leaks... the bike is 'brand new' 2008, first noticed some coolant come off the skidplate at about 150 miles. Sadly, I bought the bike at the end of the season so its no longer in warranty.

With a bike being so new... is it possible the impeller is bad? Is replacing the seals a fix or a bandaid?

Obvouisly, I'm quite bummed about this considering the age and mileage of the bike.

Whats the next step? Replace everything? Replace the seal? Tear down and inspect?

your seals could be bad, but your impeller may be scratched up too.

unfortunately, there's no way to tell unless you get it apart and take a look.

i've done this twice on my '05. I buy the necessary parts, then just return the ones i don't use.

Almost all my friends ride Yamaha and none of us have had problems except for me... is this specific to the WR450? Do the YZ's and WR250's have this same problem?

I seriously think the stock water pump seal is junk. If you pull the seal and shaft out and put the seal on the shaft in whilst in your hand you can see the seal does not have a tight fit and theres a gap on one side. I went to the local bearing shop and matched up a seal and used that. It cost about $5 here as opposed to $22 and so far (1200km) no leaks. Where as the factory one leaked during the few few months!

Make sure its just not the overflow line leaking down into your skid plate. I thought I had an issue until I realize it was that. You should also have some milky oil and also loosing some fluid from your rads if it was due to the seals.

I just changed the seals in mine about 400 miles ago with no leeks yet.

Make sure its just not the overflow line leaking down into your skid plate.

Good point... i never looked, just assumed.

I'm a little confused though, doesn't the overflow line go from the rad back to the tank? Isn't it sealed? Where is the line you are referring to?

Yes but there is another from the overflow down to where all the carb vent lines go. Just trace them from your overflow up through your subframe.


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