Leak at Thermostat

[SupraSabre]

DeJa Vu.................almost a year later and the same problem is back...........a leak at the thermostat cover...........last year I replaced the o-ring.....torqued the cover to spec......any suggestions??.........are there other options (different o-ring or gasket, some type of sealant (form-a-gasket)...............thanks for any input..

Try the thicker O-Ring! I feel the OEM o-rings were too small to begin with.

 

[Blrfl]

Is your leak coming from the joint where the two parts of the housing meet or is it coming from one of the hoses?

The hose clamps on the thermostat are known leakers, and the temperatures we've been experiencing in this part of the country are ideal for producing clamp-related leaks.

--Mark

 

[kubota35]

Try the thicker O-Ring! I feel the OEM o-rings were too small to begin with.

Bob, thanks for getting back...........is there are p/n for this?.........or a vendor (bike bandit, etc.)

 

[kubota35]

Is your leak coming from the joint where the two parts of the housing meet or is it coming from one of the hoses?

The hose clamps on the thermostat are known leakers, and the temperatures we've been experiencing in this part of the country are ideal for producing clamp-related leaks.

--Mark

Mark, thanks for your input........I'm positive the leak is not coming from any of the hoses attached to the thermostat cover.........seems to be leaking where the cover meets the thermostat housing...previous comment suggested a thicker o-ring (I believe the one on is 2mm thick)...

 

[dduelin]

Bob, thanks for getting back...........is there are p/n for this?.........or a vendor (bike bandit, etc.)

I just took the old one to an industrial rubber & gasket supplier and asked for a match. It was a long time ago but I think they gave me a 3/32" x 1.75". OEM is 2 x 43.5 mm.

 

[SupraSabre]

Bob, thanks for getting back...........is there are p/n for this?.........or a vendor (bike bandit, etc.)

I don't have one...I have yet used one... I've used the oem, but never felt like they were big enough.

 

[kubota35]

I just took the old one to an industrial rubber & gasket supplier and asked for a match. It was a long time ago but I think they gave me a 3/32" x 1.75". OEM is 2 x 43.5 mm.

thanks for getting back.............a friend at work is very good at helping with this sort of retrofit..........your info. is appreciated........

 

[kubota35]

okay, i'm back and i have "my tail between my legs" to Byron as I now know my leak on the st came from a loose clamp...........one connecting to the t-stat housing...........with the help of a friend, we made a pressure tester and put around 12 psi into the bike..........leak showed up..........this leak dripped down and eventually wound up at 6 o'clock on the t-stat cover....tightened the hose clamp and waited....leak seemed to have stopped......thanks for all of your input..
kb35

 

[Blrfl]

tightened the hose clamp and waited....leak seemed to have stopped......

You may find that the leak comes back next year after the clamps have been through some heat cycles and the bike is allowed to get cold. The problem seems to be related to the fact that the aluminum fittings shrink faster than the steel clamps, so you get a slight leak when the bike is cold that goes away as it warms up. I solved the problem with constant-tension clamps and haven't had so much of a whiff of it since.

--Mark

 

[970mike]

You may find that the leak comes back next year after the clamps have been through some heat cycles and the bike is allowed to get cold. The problem seems to be related to the fact that the aluminum fittings shrink faster than the steel clamps, so you get a slight leak when the bike is cold that goes away as it warms up. I solved the problem with constant-tension clamps and haven't had so much of a whiff of it since.

--Mark

Did the same with my clamps along with new hoses.

 

[kubota35]

thanks for the reply.........would you recommend the Breeze clamps?.........and I'm assuming I'll need to pull the hose vs. removing the band of the clamp and slipping around the hose.....

 

[Blrfl]

thanks for the reply.........would you recommend the Breeze clamps?

I do. There are probably others clamps that work just as well. The whole discussion about that from the time I decided to solve the problem until I actually did is here.

...and I'm assuming I'll need to pull the hose vs. removing the band of the clamp and slipping around the hose.....

I pulled the hoses on the thermostat and removed the band for the two at the fittings on the engine. The good part is that all five of the chronic leakers are at the top of the cooling system, so you don't lose that much coolant if you pull the ends off.

--Mark

 

[kubota35]

thanks again for the info...........I'll order some Breeze clamps...............any tips on removing the hoses? They can be difficult as they might not have ever been removed before.....appreciate the info..
kb35