Coolant leak at head

[Vdriveboater]

Well I may have just caused myself a major issue. I fired up the XII after it's been sitting for a couple of weeks and it was leaking gas badly. I finally got to it this evening by removing the left side case, covers and the coolant reservoir. I pinched off the coolant hose coming from the rad cap at the end that goes onto the reservoir to stop any leaking there so that I could focus on the source of the fuel leak. Before I fired it up again, I thought that maybe a float was sticking, so I grabbed a 17mm wrench and tapped several times on the front of each bowl. I fired it up and let her run about 5 minutes from cold (49F ambient) and there were no fuel leaks, so I surmise it was a sticking float. I just had all the carbs out and everything checked good so I'm not sure why it would be sticking. Anyway, after I shut it off and wheeled it back into the garage, I noticed something dripping on the right side and found it was coolant. I fired it back up and saw it's leaking from the place that the head fits onto the block at the right cylinder, and it's coming out quite a bit (see video). The temp gauge was just starting to go up from its cold resting place, so the thermostat is probably not even starting to open. I have no idea if pinching off the overflow hose with the engine not being up to operating temp could have any impact on this, but regardless, it is what it is, a major coolant leak that isn't going away on its own.

Voyage coolant leak.mp4

(4.24 MiB) Downloaded 14 times

I don't have the time or energy to remove the carbs again, disassemble the head and attempt to fix this, but I am going to show the video to a local shop and see what they have to say. The bike is beautiful with 14K miles and runs and drives like a dream, has brand new tires. What should I do?

[Vdriveboater]

I just found this post from 2014 -- could this be what I'm seeing, and if so, what is the likely "source" of the leak?
https://www.amervoyassoc.org/forum/viewtopic.php?t=8072

[triton28]

It sounds as though your coolant system may have endured temporary elevated back pressure with the pinched hose. And while it would not be off the Richter scale it may have been enough pressure to cause a failing pipe/hose to show it's weakness whereas new condition pipes/hoses probably would not have shown this condition with such a short time of operation.
As seen in the pics from the post you referenced and your video, coolant flowing from the spark plug cavity drain holes generally is coming from the coolant system above the cylinder head in some form of a leak; usually a bad hose or a rusted steel pipe, hopefully a loose worm gear clamp.
Reinstall the hose to the overflow tank, the overflow tank, top up the coolant and with the coolant pipes/thermostat housing above the cylinder head exposed to view run the bike up to temperature, or obvious leaking, and check for evidence of where a leak may be coming from. You may get lucky and with the return to normal operating pressure it may seem as though the leak is gone but be sure to check all the involved parts carefully.
Personally I would reintroduce the same "pinched hose" circumstance with the hoses/pipes above the cylinder head fully exposed to view and find the weak link in the system BUT, that's just me, YMMV.
Normally the pressure buildup in the system will relieve itself at 15 lbs through the hose to the overflow tank but with the hose pinched off it couldn't so you may have had a short time of over pressure.
I highly doubt the head gasket is at fault and you find some simple explanation from the hoses/pipes/housing/clamp equipment.
It's incredible what a buildup of pressure can do even in small amounts.
Always ensure the overflow hose/tube is free flowing to the tank or to a catch container if tank is removed and the engine is to be operated. The system can always be topped up after any testing/service
Remember these bikes are 21 years old if it is the most recent model year: 2003.
And if the installed equipment is original then those items are also 21 years old at best and if one hose/pipe is showing signs of failure then the other hoses/pipes may not be far behind.
These old bikes are great but they do have their moments.
What ticks me off is the gradual disappearance of OEM parts from the manufacturers, but that is another story.
Dave

[Nails]

Not really related, but old radiator caps get awfully skanky. I'd replace it as a matter of course. And I want to mention that it's easy to misroute the overflow hose in a way that pinches it to the frame. (My miserable bike came to me that way.)

[GrandpaDenny]

Looks to me like water draining out of the spark plug well. That's a drain hole - they get plugged. That water looks awfully not green to be coolant. Take a coat hanger or a scribe or something and poke it in that hole to clean it out. One of a couple of reasons why we say to blow the spark plug well out really well with high-pressure air before pulling a plug. You'd be amazed what collects in there.

[Vdriveboater]

Looks to me like water draining out of the spark plug well. That's a drain hole - they get plugged. That water looks awfully not green to be coolant. Take a coat hanger or a scribe or something and poke it in that hole to clean it out. One of a couple of reasons why we say to blow the spark plug well out really well with high-pressure air before pulling a plug. You'd be amazed what collects in there.

Yes Denny, I will run a thin wire through that little weep hole to make sure it's clear. FYI, the "silica free" coolant I use is more yellow in color than green, and it was flushed and new coolant added less than 500 miles ago. The leaking fluid is definitely coolant.

[Vdriveboater]

It sounds as though your coolant system may have endured temporary elevated back pressure with the pinched hose. And while it would not be off the Richter scale it may have been enough pressure to cause a failing pipe/hose to show it's weakness whereas new condition pipes/hoses probably would not have shown this condition with such a short time of operation.
As seen in the pics from the post you referenced and your video, coolant flowing from the spark plug cavity drain holes generally is coming from the coolant system above the cylinder head in some form of a leak; usually a bad hose or a rusted steel pipe, hopefully a loose worm gear clamp.
Reinstall the hose to the overflow tank, the overflow tank, top up the coolant and with the coolant pipes/thermostat housing above the cylinder head exposed to view run the bike up to temperature, or obvious leaking, and check for evidence of where a leak may be coming from. You may get lucky and with the return to normal operating pressure it may seem as though the leak is gone but be sure to check all the involved parts carefully.
Personally I would reintroduce the same "pinched hose" circumstance with the hoses/pipes above the cylinder head fully exposed to view and find the weak link in the system BUT, that's just me, YMMV.
Normally the pressure buildup in the system will relieve itself at 15 lbs through the hose to the overflow tank but with the hose pinched off it couldn't so you may have had a short time of over pressure.
I highly doubt the head gasket is at fault and you find some simple explanation from the hoses/pipes/housing/clamp equipment.
It's incredible what a buildup of pressure can do even in small amounts.
Always ensure the overflow hose/tube is free flowing to the tank or to a catch container if tank is removed and the engine is to be operated. The system can always be topped up after any testing/service
Remember these bikes are 21 years old if it is the most recent model year: 2003.
And if the installed equipment is original then those items are also 21 years old at best and if one hose/pipe is showing signs of failure then the other hoses/pipes may not be far behind.
These old bikes are great but they do have their moments.
What ticks me off is the gradual disappearance of OEM parts from the manufacturers, but that is another story.
Dave

Thanks for the tips Dave. I'm hoping it's a loose clamp. If the head hose failed, at least it's the right side which I believe is still available (left side has been obsoleted). I'll report back with my findings when I have them.

[Vdriveboater]

After removing the battery and airbox, I noticed that the #3 spark plug hole was filled with coolant, and I could see coolant on the RH tube where the hose attaches to the head. I drained the coolant, blew out the plug hole with compressed air, and removed the hose, and upon inspection it was rusty in the ID at the end that attaches to the head tube, so I cleaned it thoroughly with a small wire brush and made sure everything was clean before installing. I also used a small rotary tool with a stone to clean up some of the tube where the hose attaches. After re-installing and filling with coolant, I fired her up, and after about 3 minutes of idling, it started leaking again, right where the clamp sits, so it's obvious there is a tiny hole or cut in the rubber that I couldn't see. I just ordered a replacement RH hose from Partzilla and will report back after it arrives and I get it installed.

[triton28]

I am glad you found the leak and can repair it with relative ease.
Dave