Water leak question.

jkevinlilly · Post by **jkevinlilly** » Sun Mar 21, 2010 8:09 pm

Pinky (74 GT 750) has developed a leak. Yesterday I checked the coolant level and it was down a bit. Topped it off, started her up cold, and let her idle for a few minutes. Then coolant started disharging from the cooling system overflow/pressure relief hose. The coolant was only lukewarm. Took her for a ride, did not appear to loose any additional significant amounts of coolant, temp gauge stayed where it normally does. Let her sit overnight, started her up, and went through the same routine again.

Ideas??

Kevin

tz375 · Post by **tz375** » Sun Mar 21, 2010 9:24 pm

From teh symptoms, it sounds as if the pressurization occurs at startup and doesn't continue to deteriorate as it heats up or runs.

That tends to suggest that it's not a head leak unless the head leaks until the block expands and increases pressure on the gasket (barrels expand more than studs and sleeve nuts).

If that were an issue, then you could try to re-torque the head.

Is it possible that there's some problem with the thermostat? It's an unusual design in that it when it gets hot, it opens the main hose passageway and closes off the bypass. If it's damaged in some way, could it be partially obscuring the bypass?

Buffalo-guy · Post by **Buffalo-guy** » Sun Mar 21, 2010 11:33 pm

If the discharge is from the overflow tube, could it be something as simple as a malfunctioning rad cap. They are supposed to pressure test to 15 lb's, maybe it's just old and tired, like the rest of us. Well, some of us anyway. Cheers.
Fred

Barry S. · Post by **Barry S.** » Mon Mar 22, 2010 4:42 am

How full are you filling it, it's supposed to be way down in there where the 2 tubes feeds it to the overflow tank under the gas tank. If you fill it to the top it will overflow when running.

Post by **oldjapanesebikes** » Mon Mar 22, 2010 11:33 am

I'd agree with Barry and Fred, and in that order also. Possibly a bit too full, or perhaps a rad cap problem. If the level holds steady once the leak from the overflow stops, then I wouldn't worry about it.

rngdng · Post by **rngdng** » Mon Mar 22, 2010 6:14 pm

You know, it did that to me one time. I never resolved it, as it quit happening. I think it may be the radiator cap as well, but it did happen before and simply went away. I don't know.....

Lane

h2thief · Post by **h2thief** » Mon Mar 22, 2010 7:51 pm

mine will puke out th4e coolant if I fill it to the top too. I just make sure I can see it in the fill tube and call it good....

jkevinlilly · Post by **jkevinlilly** » Tue Mar 23, 2010 5:30 am

I may have overfilled it. Not the raditor cap, unless I bought a bum one. This happed once last year, I figured the raditor cap, so replaced it. Now it has happened with the new radiator cap. I'll keep an eye on it and see what develops.

Thanks
Kevin