Coolant Leak

[92135]

I am a new K100 owner with little knowledge of the bike. I have a coolant leak just to the rear of the oil-water pump from what appears to be a weep hole of sorts. This is a '85 K100RT. Can anyone shed light on what may be going on here and a fix?

[roy]

I am a new K100 owner with little knowledge of the bike. I have a coolant leak just to the rear of the oil-water pump from what appears to be a weep hole of sorts. This is a '85 K100RT. Can anyone shed light on what may be going on here and a fix?

The seals on the shaft of the water pump are leaking. The shaft drives both the oil pump and water pump. The weep hole is between the seals on the respective pumps. If the pump is original on your 85 it will probably be less expensive to replace the whole pump than buy the parts to rebuild what you have. When my 85 failed the drive shaft & impeller where both obsolete. The cost of these parts plus the seals was about 75% of a new pump assembly. Rebuilding these also requires some special seal installers be made.

Good luck

Roy

[bikerfish1100]

Replacement is an easy DIY fix, no need to bother with the dealer.

[35675]

I had a similar problem on my '85 RT about 15 years ago. I just removed the pump(s) and re-applied sealant to the face where it seats on the engine case. BMW didn't use a gasket and the factory sealant was leaking. No problems since then. Of course, it could be worn out, but, other than having to drain and replace the coolant, this is a pretty thing to try.

[grandparipper]

I had the same issue on my 1991 K100RS. Take it off yourself and have it looked at by the service dept. If they are as nice as the folks in Tacoma, they will describe what a cheapskate like me can do on his own, and what really ought to be done by the service guys. The book says you can replace the bushing by using a socket and hammer. They now use a ceramic bushing that last longer, but will crack using the socket set method. I had to order a new shaft and bushings, pay them next to nothing to put it together, then I reinstalled it without any challenges. Much less than a new one, but the new one would be warranted for 2 years I think. You make the call on the value of the warrantee.

Fix it and get out there!

Grandpa Ripper