Coolant relief hole??? on WR450

Yeesterday while I was trying to get my bike started(it was about 40 degrees) I had some coolant spill out from a small hole at the bottom of the pump housing. It spilled before I ever got the bike to crank. It was not alot, but equal to a small capful, maybe. It never leaked that I could tell once I got it to start, even through about 25 miles of riding.

Can someone educate me on this? :) One day maybe I'll know enough to actually help someone else.

I saw on one of those "other" websites where a few people determined that the water pump seal was damaged. I haven't noticed any posts here like that. Anyone?

My 2000 WR400 used to weep slightly out of the waterpump hole when cold... A few people said to replace the water pump seals, but I never lost enough coolant that I worried about it, I never even topped off the bike between coolant changes. I have riding buddies that have the same, and I always blamed it on the cold weather up here. I DO remember the 98 and 99 WR guys that did have trouble with water pump seals and also the shaft.I wouldn't worry too much, unless the leak gets worse, OR you start getting coolant in the oil. My 2 cts.


I just noticed that my wr 450 is leaking out of the weep hole too. It doesnt leak much, usally what ever is in the over flow in a few hours of riding. What do you usally do to solve this? Just change the two oil seals and if that doest cure it then the shaft too?? :)

Big D, That sucks!!! I would definately replace the seals, and take a close look at the shaft too. I hope this doesn't end up being ANOTHER problem area for these bikes!! I am starting to get a little nervous... :)


Mine did that a while ago and I brought it to the dealer to get fixed. He said it was due to the high pressure wash I use. He replaced the seals on the pump and it hasnt happened since. :)

Also, using a coolant (anti-freeze) that doesnt contain "silicates". Of course, I use stuff I get from work (Toyotas red) and it contains no silicates or borates. Mix it 50/50 and I still add some conditioner. Helps to extend it, prevent electrolysis and allows for more heat transfer. Borates create corrosion problems also. But you'd have to leave it in for a long time, which most dont do on motorcycles. And regardless of its freezing, boiling protection, always change it at 2 year intervals max. I have never had a water pump seal leak on mine as of yet.

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