leaking coolant,06 yfz 450


i have a 06 yfz450 that has just recently started to leak coolant out this rubber tube that is conected to the bottom of the water pump housing.it dripes out pretty fast when the motor heats up and dosent stop.my buddy thinks the water pump is thundered.

Depending on how long the leak has gone unnoticed will really determine the fate of the parts you'll need. I found my leak really early, in fact just in the stages of the first few droplets. I got lucky and only needed to replace the outer waterpump cover.

If you don't know how long it has been leaking, your best bet is to go ahead and reseal everything. Someone who has been there will hopefully correct me or let me know if I got everything.......but you can count on an outer seal, water pump shaft, water pump shaft o-ring, water pump impeller, water pump shaft bearings, and a seal for the side case.

Definitely will need some mechanical skill and tools to do the job.....but its not rocket science.

Doc gave you good advice. :bonk:

There are two seals on the water pump shaft. The one in the back of the pump is the water seal. The one in the case is the oil seal. There is a cavity between the seals with a drain ( the rubber hose you mention ). Yamaha did this to prevent coolant from getting in the engine oil or visa versa if one of the seals fail. Anyone who had a Banshee that ended up with something that looks like a milk shake in the gear box can appreciate this. I haven't seen an oil seal fail yet but have seen quite a few of the water pump seals fail ( mine failed at less than 10 hrs ). If the engine has over 100hrs on it, I would replace both shaft seals, the pump, the bearing, and the cover seal. Less than 100hrs and you could probably get away with the cover seal and the water seal. It is very important that when you replace the water seal, you lubricate the lip that contacts the shaft with a good synthetic grease. I've changed several of these water seals and they all appeared to fail from lack of lubrication. All but one had very low hours. None of the replacements have failed yet. It isn't a real hard job if you are mechanically inclined but you do have to take a lot of the right hand side of the quad apart to get the pump off. You wouldn't want to do without at least an exploded view of the side cover and the pump so you can get all the little pipes and o-rings back in the right places. Good luck!!

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