Need help fast! '03 YZ450F leaking coolant


6 replies to this topic
  • Grieby54

Posted September 07, 2007 - 08:45 PM

#1

My riding buddy and I are going riding tomorrow and we've been working on his bike all night trying to get it in tip top shape. Well, we decided to replace the coolant. So I took the bottom bolt out of the water pump, drained the coolant, replaced the bolt, then added new coolant. I wasn't paying much attention to if it was leaking before or not, but I tipped the bike sideways to get the coolant in the left side radiator as well, then when I returned to the right side, I found coolant dripped out of a weep hole on the bottom of the water pump. What's the deal and how do I fix it???

  • grayracer513

Posted September 07, 2007 - 09:07 PM

#2

Coolant is tricky stuff. The first thing to ask is whether it's really still leaking, or if it's just kind of left over from stuff that ran across that surface when you drained it?

But if it is really leaking from the weep hole in the case, or appears to be, first be sure there's still a copper washer on that bottom bolt you had out. Then, you get the bad news.

A leak from the weep hole is caused by a failed water pump impeller shaft seal. The hole is the outlet from a passage designed to release coolant leaks to the ground rather than let them get into the engine oil (or vice versa), and it means you need to replace the seal, and possibly the shaft, if the seal has worn a groove in it. That means pulling the right engine case cover off.

But you might try running it. Water pump seals may leak when cold but not when warmed up. If you keep a careful eye on it, you might get your ride in. But ALWAYS bear in mind that it's dangerous to open a hot cooling system. Let it cool a little before you check the level.

  • Supafreak_711

Posted September 07, 2007 - 09:34 PM

#3

Thank you very much grayracer. (I'm Grieby's riding buddy, and owner of the ever problematic bike)

The weep hole is where the leak is coming from, and its fairly slow and steady (as it, drip.... drip.... drip... etc). I will try warming the bike up before I ride tomorrow and pray that it will at least work for the day. If it is still leaking, I can always just keep adding coolant throughout the day right? I'm not sure how practical this is (whether or not I will go through to much coolant trying to keep it full) but I really need to ride tomorrow.

Thanks again for the help! :thumbsup:

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  • PatrickM

Posted September 08, 2007 - 06:20 AM

#4

The same thing happened to my 99 YZ400F and it stopped when I replaced the seal that was spoke of in an earlier post.


the seal should be cheap but the shaft may be a bit more costly. Just do the seal replacement and it should fix your problem.



Good luck!!!!!


Patrick M.

  • Ga426owner

Posted September 08, 2007 - 10:13 AM

#5

The same thing happened to my 99 YZ400F and it stopped when I replaced the seal that was spoke of in an earlier post.


the seal should be cheap but the shaft may be a bit more costly. Just do the seal replacement and it should fix your problem.



Good luck!!!!!


Patrick M.



not necessarily. If the shaft has grooves on it ...no seal by itself will repair it. The shaft and the seal are pretty cheap - 20.00-30.00 max.
I replaced both on my 03 when it did the same thing:thumbsup:

  • Supafreak_711

Posted September 08, 2007 - 06:50 PM

#6

Is there any chance that water could be getting into the motor through this leak? We didnt have the bike running for long, but it seemed to have alot of white smoke (my dad says he saw it comming from the exhaust, but I know there was quite a bit comming from the water pump area).

  • grayracer513

Posted September 08, 2007 - 08:15 PM

#7

The way the pump is designed, there are two seals on the shaft, one for oil and one for water. There is a space of about 5-7 mm between these seals, and this space is open to the outside by means of the weep hole where your leak is.

When everything is working as it should, the answer is no, it can't get into the engine. Even if it did, it couldn't get to the combustion chamber. That would take a bad head gasket or similar problem. Also, the oil would take on the appearance of a sickly looking vanilla milkshake if there were coolant in it.





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