My 2001 yz426f has a problem with engine coolant leaking from the weep hole

8 replies to this topic

Posted October 31, 2009 - 07:26 PM


My 2001 yz426f has a problem with engine coolant leaking from the weep hole under the side housing that holds the water propeller. This seems to happen only when the bike is standing still, even when it’s only a few minutes. Once it is moving again it seems to slow down or sometimes stop. I have changed the O-ring for the propeller housing and flushed the coolant but it still happens. The bike runs great and has tons of power, it starts on the first couple of kicks but I cannot stop for any length of time without shutting it off or it starts blowing out coolant.Is it safe to ride it? How can I fix this problem??

  • tribalbc

Posted October 31, 2009 - 07:57 PM



Posted November 01, 2009 - 03:17 PM


Hey guys, I tore down the water pump and replaced the pump gasket. Bike still seems to be leaking slowly from the sweep hole while standing still. I rode it for about an hour and the bike did not overheat. Any suggestions???

  • dbshea

Posted November 02, 2009 - 08:13 PM


Had the same thing happen to mine, replaced the impellor seal and it fixed it right up

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  • Alternative

Posted November 02, 2009 - 10:12 PM


Did you replace the shaft?

Edited by Alternative, November 03, 2009 - 02:06 AM.


Posted November 04, 2009 - 09:43 PM


No I did not replace the shaft or the impeller seals. The bike has been sitting on a stand and loosing a lot of coolant. I guess I will have to replace everything else to stop this leak correct?

  • tribalbc

Posted November 05, 2009 - 06:43 AM


Do the shaft, 2 seals and bearing. $25 in parts and then you know it's all good. Just involves removing left side crankcase cover.

  • Alternative

Posted November 05, 2009 - 03:49 PM


^^^ What he said.


Posted November 06, 2009 - 07:06 AM


Thank you for all your prompt responses, I was wondering were can I get these parts, because they want about $60 for a shaft + bearings, gaskets & seals = $100.


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