YZ400 leaking coolant

[theclone]

I have a coolant leak on my bike. I lost quite a bit when riding today. It leaks out of the water pump area, and it leaks more when the bike is running rather than sitting. Is this a somewhat common, easy to fix problem? I should be good if I replace the water pump cover gasket, correct? Or is it more serious?

[Gerry B]

Your seals have gone bad. You need to replace them. You need to remove the whole side cover to getto them. The leak is coming from the small weep hole at the water pump. There are 2 seals. You might be OK if you just replace the outer seal. You need to remove your impeller and pry the old seal out of there. It's not a difficult job.

[dougstar64]

Run your bike and tell us EXACTLY where coolant is coming from, there should be a small hole under the water pump (weep hole), if its coming from there then its like gerry said, if its coming from somewhere else around the water pump housing then like you said, the gasket.

[theclone]

OK I just changed the water pump seals and flushed the radiator. started putting fresh coolant in and the thing leaks like a faucet! here's a pic to show where its leaking from: (sorry for the huge pic)

what the hell! I was all proud because I thought I fixed the problem but I just made it worse. I dont get it, this was supposed to be simple.

[rdefonce]

OK I just changed the water pump seals and flushed the radiator. started putting fresh coolant in and the thing leaks like a faucet! here's a pic to show where its leaking from: (sorry for the huge pic)

what the hell! I was all proud because I thought I fixed the problem but I just made it worse. I dont get it, this was supposed to be simple.

Clone, I've never had a leak in my YZ; looks like the seal where the metal pipe goes into the case; is that the one you replaced? Good luck, hope you get it fixed soon.:-o

[theclone]

Well I fixed the leak for the most part. turns out the rubber o-ring that was sent to me was just a hair thinner than the original one. luckily they gave me 2, so I just put both in there and it worked fine.

but there is still a very slight leak coming from the weep hole, which was where it was leaking from in the first place. but its soo small I'm not gonna worry about it too much, just throw some coolant in the trailer just in case.