yz426 leaking oil after replacing seals in water pump

3 replies to this topic
  • joallen001

Posted November 22, 2006 - 08:20 PM


This is my first time ever doing in motor work so maybe I messed up somewhere. I installed a new gasket, 2 seals for water pump, shaft for water pump and bearing. Seems to me like the oil may be coming from the upper oil line and maybe the lower also. There is also some oil coming out from around the oil filter. Should I pull this all apart and start over? I almost think the antifreeze was mixed with the oil because I drained the antifreeze out and it was a lot darker than what I just put in. Can someone describe how the seals go in. I thought they were side by side and the spring in them faces away from each other? any help or ideas appreciated I will also mention that this motor is in a hybrid quad and I put 2 quarts of oil in it.

  • grayracer513

Posted November 22, 2006 - 08:35 PM


Oil and coolant mixed turn into something that looks vaguely like a chocolate milkshake, not darker coolant. The WP shaft has two seals, the inner one for oil and the outer for coolant, and there's a gap in between that leads to a hole running out below the water pump. The purpose of that is to give either fluid somewhere to go besides into the other one, expressly so that they won't mix.

You are correct as to the orientation of the seals. The inner seal lip faces in toward the oil, and the outer one faces out toward the coolant.

I'm confused by your reference to an upper and lower oil line, as the two oil lines attach to the engine at the same height on opposite sides. Also, I don't know what the capacity of the oil tank you are using is, but 2 quarts would be too much for a YZ426 motorcycle. It's not a question of how much the engine will hold, because it doesn't really hold anything anyway. The oil is mostly carried in the tank while running, and the engine can have as much oil in it as the tank will hold. If you exceed that, it will blow out the breather tube.

On the oil filter, you may simply have dropped or damaged one of the 4 O-rings. Pull the cover and check.

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  • joallen001

Posted November 24, 2006 - 05:12 PM


There was a line I had to unhook on the top and the bottom. I thought they were both oil lines. As far as the seals go. You say the inner seal lip faces towards the oil. Does this mean the side where you can see the spring faces towards the oil and towards the coolant.

  • grayracer513

Posted November 24, 2006 - 06:05 PM


Does this mean the side where you can see the spring faces towards the oil and towards the coolant.

Yes it does.

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