Coolant leak - near waterpump cover

jho410

Subscriber
Joined
Apr 30, 2002
Messages
272
Likes
0
#1
I noticed that my bike was starting to leak coolant from somewhere near the waterpump cover. I looked more closely and see that it is not waterpump cover (or gasket) but a small hole in the case just beyond the waterpump cover. The hole looks as though it is supposed to be there - factory made. It's about 1/8" wide.

Is this a vent? Is it stuck open? Does anybody know anything about this?

I plan on taking the entire waterpump cover off and then the entire assembly out but I wanted to know what I am looking for.

Thanks - Jeff
 
Joined
Mar 6, 2001
Messages
48
Likes
0
#2
Not sure on a YZ, but on my cr250 that hole is there to indicate when a water seal and/or oil seal goes bad. If water is coming out, then the water seal behind the water impeller is leaking. You will need to replace both seals (its best to replace both even if only one is bad) and inspect the water impeller shaft for nicks or burrs that could eat into the new seals.

Again, not sure on a YZ, but on a CR you have to take off the right side crank case cover to remove the impeller shaft and get to the seals. An easy job, but takes a couple of hours. And might need a bearing puller to get a bearing out to get to the oil seal. Someone please correct me if this isn't true on a YZ.

Jon
 

jho410

Subscriber
Joined
Apr 30, 2002
Messages
272
Likes
0
#3
Makes perfect sense and after looking at the bike more, it appears that the YZ is just like the CR in that department. I have the parts and will repair said seal and hope for the best. Thanks for the input Chooch.

Any advice on seal removal and replacement? I figure I don't need to worry so much about the removal but not sure about the replacement. A little lithium soap and slide in?
 
Last edited:
Joined
Mar 6, 2001
Messages
48
Likes
0
#4
Well, I just did this myself, and followed the instructions in the Clymer manual. Basically, it said to pack both seals with grease and press them in (make sure they are facing the right direction; on the CR both seal lips had to be facing away from eachother). I used a socket that was as big as the outside lips on both seals to press them in evenly and as far in as they would go, and they pretty much just slid right in. For the bearing, I used a socket to press it in as well, but needed to use a hammer on the socket to drive the bearing in. Just make sure you are not pressing the bearing on its inner ring, as that will damage the bearing. You also should probably grease the impeller shaft and twist it as you are inserting it to make sure it goes in smoothly and you don't damage the seals.

I think if you do a search for "water impeller" or "water seal" you will find more info on this topic. Good luck,

Jon