Yesterday while riding my 92 K75S I could smell the anti-freeze from my radiator. Small droplets would hit the exhaust and create a noticeable smell. This morning I could see a few drops of coolant on the floor beneath the bike. I removed the fuel tank and many of the body parts. I had hoped to be able to spot a location from where the leak originated, e.g. cracked hose or clamp that needs tightening. Alas, the leak is coming from the center of the radiator.
I last repaired a leaking radiator core in 1974 by using a torch and solder on a removed radiator from a car (64 Triumph TR4) that I was working on. I wonder if a similar method would work on the K75S radiator. I have done some looking on the 'net and found some other threads with various repair options. Some have indicated success with a "stop leak" additive to the coolant. I would be a bit concerned about such a product negatively affecting the water pump.
One respondent indicated making a repair by using an externally applied putty-like material. Several folks indicated a lack of success in getting automotive radiator repair places to attempt a repair to the K75S radiator.
Following are links to the past threads that I've found related to this topic -
https://forums.bmwmoa.org/showthread.php?19850-1987-k75s-leaking-coolant
https://forums.bmwmoa.org/showthread.php?73177-87-K75s-Coolant-Dripping
https://forums.bmwmoa.org/showthread.php?52201-Coolant-Antifreeze-for-1994-K75
https://forums.bmwmoa.org/showthread.php?6657-Radiator-Leak-amp-Part-s
https://www.motobrick.com/index.php?topic=10735.0
https://www.k-bikes.com/forums/56-other-k-bikes-discussion/18987-how-much-coolant-leak-normal.html
http://www.k100-forum.com/t4231-we-ve-got-a-coolant-leak
I last repaired a leaking radiator core in 1974 by using a torch and solder on a removed radiator from a car (64 Triumph TR4) that I was working on. I wonder if a similar method would work on the K75S radiator. I have done some looking on the 'net and found some other threads with various repair options. Some have indicated success with a "stop leak" additive to the coolant. I would be a bit concerned about such a product negatively affecting the water pump.
One respondent indicated making a repair by using an externally applied putty-like material. Several folks indicated a lack of success in getting automotive radiator repair places to attempt a repair to the K75S radiator.
Following are links to the past threads that I've found related to this topic -
https://forums.bmwmoa.org/showthread.php?19850-1987-k75s-leaking-coolant
https://forums.bmwmoa.org/showthread.php?73177-87-K75s-Coolant-Dripping
https://forums.bmwmoa.org/showthread.php?52201-Coolant-Antifreeze-for-1994-K75
https://forums.bmwmoa.org/showthread.php?6657-Radiator-Leak-amp-Part-s
https://www.motobrick.com/index.php?topic=10735.0
https://www.k-bikes.com/forums/56-other-k-bikes-discussion/18987-how-much-coolant-leak-normal.html
http://www.k100-forum.com/t4231-we-ve-got-a-coolant-leak