03 yz450f leaking radiator fluid!!!

3 replies to this topic
  • boyonblue52

Posted January 03, 2006 - 01:36 PM


I went out to fire my 450 today to get it ready for this weekend (goin riding SX) and i saw after it started there was radiator fluid on the ground just a small amount and i saw it was coming from the weep hole off the block by the water pump. Yamaha said my seal went even though it never leaked before i put it away for the winter. It only has 25 hours total on the bike. What would cause this? :applause:

  • grayracer513

Posted January 03, 2006 - 01:57 PM


Coolant dripping from that port is indeed due to a failed seal. Water pump seals are funny critters, and what makes them leak and stop leaking has bugged mechanics for decades. Could have been any number of things; shrinkage, inactivity, electrolysis, who knows. There is a small chance that it will quit once it warms up, and not leak anymore for a while longer. But plan to replace it soon.

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  • boyonblue52

Posted January 03, 2006 - 02:28 PM


Yeah i thought about that but i just ordered the part and they (Yamaha) said it could also be my bearing in there but the thing is it only has 20hrs on the bike so i said forget that it couldnt be gone already so i went and just ordered the seal. Also it never leaked before during the summer and even before i put it away on my last ride it never did so what ya think? just the seal or could the bearing have gone too? My buddy with the same bike exactly never had a problem and he thought the bearing might have over heated but i never rode it hard enough to have it over heat i was still just puttsin around to break it in never past half throttle like the manual said to.

  • WR450F_RDR

Posted January 03, 2006 - 05:29 PM


I had the same thing happen on my WR. it turned out to be the seal only, easy fix. I wouldn't buy the bearing until you inspect it.

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