Coolant pipe seepage

This has probably been discussed here before, but since Ponch mentioned this problem, I decided to discuss it here. (This essay is re-posted in-part from my thread "Nomad Blogging Continues" in the Custom/Cruiser room over at the motorcycle-usa.com forums. All my other mods and maintenance are recorded there in extensive detail in case anybody wants to read themself to sleep.)
*******************************************888
Day 1465
27,881 miles

This was one of my reservations about buying a liquid cooled bike, and unfortunately while the Nomad has a pretty solid cooling system it has one weak spot that is the result of poor design. Fortunately it can be fixed cheaply. Unfortunately it's a pain to do.

The issue is the coolant pipe going into the top of each head, which connects the radiator hoses to the heads. These are short steel tubes with a single o-ring on the end which plug into a hole bored into the top of the head. They are retained by a single small bolt each, which connects a tab (welded to the steel pipe) to the head.

Unfortunately, as the cylinders vibrate up and down on this big v-twin, they are shaking that pipe in and out of it's bore just a little, and the o-rings eventually (quite quickly in fact) wear down and start to seep coolant. The little tab and bolt arrangement is not in line with this motion, but transverse to it, and simply does not do enough to restrain the coolant pipe firmly.

My solution: a new o-ring and silicone glue.

...This seepage is very minor, and some owners may never even notice it. I typically have been adding only about 8 ounces of coolant per year to this bike. That tiny amount of seepage evaporates from a hot engine before ever hitting the ground, nor even any place on the engine where it becomes easily visible.

This is part of what makes it a bear to repair: it's burried under a lot of junk and takes lots of effort to get to. I had to remove the windshield, gage trim. gages, seat, and gas tank. Removing the gast tank involves unplugging two very reluctant electrical connectors to the gages and fuel level float, and the detachment of 6 hoses on the fuel system: two vent hoses, an overflow hose, a vapor recovery hose, the fuel return hose, and the main fuel hose to the injectors.

Four of those hoses are under the tank, and I needed a friend to hold the tank a few inches above the frame for five minutes so I could detatch them. They don't give you a lot of slack to work with. Have a rubber cap ready to cap off the gas when you detatch the main fuel hose, as it will leak quite a bit if you don't. ... I also took pains to run the tank almost dry the day before, so my friend wouldn't have to struggle with it.

Once the tank was off I drained the cooling system, (the plug is under the radiator) removed the pressure cap (under the gas tank) and removed the first upper coolant hose from its pipe. Getting to the retaining bolt on the rear coolant pipe was pretty difficult. It requires a long skinny 8mm wrench and a lot of patience. It will not unscrew completely from the head as it hits the throttle mechanism, which is not removed without removing the air filters, backing plates, associated plumbing, and the fuel injectors and intake manifold. This I was NOT going to do. I removed the retainer bolt as far as possible, and bent the tab on the coolant pipe a little until I could get it loose.

The pipe required serious persuasion with some long long-nosed pliers, and in the process I nicked up the hose-mating surface a little. I burnished both ends off well with a powered wire brush, removed the burrs I'd made, straightened the tab I'd bent and trimmed it a little so it could go back on straight with no monkey business. I cleaned it up with solvent and put it aside.

I then cleaned the bore in the head out with solvent and a rod I made similar to one for cleaning shotguns with a patch. I scrubbed it really clean (multiple times) so the silicone would stick, finally wiping with dry paper towels. I mounted a new o-ring to the pipe with silicone, slathered on some more silicone (Permatex black label BTW) and shoved it gently back in. I pressed it into the head while my friend struggled to re-tighten the captive bolt. I let the glue set up a while and took a break.

Once the silicone had time to set, I cleaned the end of the coolant hose inside, put some Permatex (orange label) weatherstrip advesive in the end of the hose and clamped it back in place. I let that set up a bit.

(Repeat on the front head, where the bolt is easier to remove, but the hole is harder to clean.)

Becuase I did not want to run the engine until the silicone had set over night, I was very careful to get out as much air from the system as possible when re-filling it. I wiggled and pinched hoses and rocked the bike side-to-side and back & forth until I managed to get nearly 3 quarts of HondaCool into it, then capped it off. Any extra air will blow out into the surge tank tomorrow, and be replaced by coolant siphoning back when the bike cools off tomorrow night. I hope. (It did.)
************************8

I'll post a little sketch of the offensive coolant pipe design in a bit.

Cadd.

[mrclean]

I just had a new o-ring and fitting replaced on mine. It seeped enough that i had residue on the number one jug.

Mine leaked a long time before it was bad enough to see anywhere without taking the bike apart. Once the tank was off, it was obvious. Not just residue but coolant.

Anyhow, here's a simplified drawing of the coolant pipe. That attatchment tab and bolt are tiny and weak, and provide little resistance to motion from the engine, as they are not in line with that motion. Consequently the coolant pipes vibrate constantly and after a couple years the o-rings wear flat & leak.

Everybody eventually glues these in with silicone, or goes back to air-cooled engines. ;)

[ponch]

This should be on Gadget's site if it is not...

[blowndodge]

thats probably whats happening to mine. I've only added coolant once in 2 years and only about 4 onces. Tomk told me his leaked onto the #1 cylinder and it was the thermostate gasket drippling all the way to the front cylinger. I get a spot or two on the bottome end near the front motor mount. i don't ever smell radiator fluid. bummer...this could be a pain in the ars..

[ponch]

To what part of the pipe did you apply silicone sealant? I would think that you would not apply silicone to the O-Ring. I do not have anti-freeze dripping anywhere or see vapor. But I do smell it. It annoys the hell out of me that a new bike (or any new vehicle for that matter) would have such niggling issues that are commonplace. I recall the mechanic at the dealer complaining that he had to remove the fuel injection to replace the O-Ring. Looking at my records, the repair was done October 12th, at 7360 miles, and the bike now has 8139 miles. So either he didn't fix it properly, or the other O-Ring is weeping. So, did you buy the O-Rings from Kawasaki?

This has probably been discussed here before, but since Ponch mentioned this problem, I decided to discuss it here. (This essay is re-posted in-part from my thread "Nomad Blogging Continues" in the Custom/Cruiser room over at the motorcycle-usa.com forums. All my other mods and maintenance are recorded there in extensive detail in case anybody wants to read themself to sleep.)
*******************************************888
Day 1465
27,881 miles


My solution: a new o-ring and silicone glue.

...This seepage is very minor, and some owners may never even notice it. I typically have been adding only about 8 ounces of coolant per year to this bike. That tiny amount of seepage evaporates from a hot engine before ever hitting the ground, nor even any place on the engine where it becomes easily visible.

This is part of what makes it a bear to repair: it's burried under a lot of junk and takes lots of effort to get to. I had to remove the windshield, gage trim. gages, seat, and gas tank. Removing the gast tank involves unplugging two very reluctant electrical connectors to the gages and fuel level float, and the detachment of 6 hoses on the fuel system: two vent hoses, an overflow hose, a vapor recovery hose, the fuel return hose, and the main fuel hose to the injectors.

Four of those hoses are under the tank, and I needed a friend to hold the tank a few inches above the frame for five minutes so I could detatch them. They don't give you a lot of slack to work with. Have a rubber cap ready to cap off the gas when you detatch the main fuel hose, as it will leak quite a bit if you don't. ... I also took pains to run the tank almost dry the day before, so my friend wouldn't have to struggle with it.

Once the tank was off I drained the cooling system, (the plug is under the radiator) removed the pressure cap (under the gas tank) and removed the first upper coolant hose from its pipe. Getting to the retaining bolt on the rear coolant pipe was pretty difficult. It requires a long skinny 8mm wrench and a lot of patience. It will not unscrew completely from the head as it hits the throttle mechanism, which is not removed without removing the air filters, backing plates, associated plumbing, and the fuel injectors and intake manifold. This I was NOT going to do. I removed the retainer bolt as far as possible, and bent the tab on the coolant pipe a little until I could get it loose.

The pipe required serious persuasion with some long long-nosed pliers, and in the process I nicked up the hose-mating surface a little. I burnished both ends off well with a powered wire brush, removed the burrs I'd made, straightened the tab I'd bent and trimmed it a little so it could go back on straight with no monkey business. I cleaned it up with solvent and put it aside.

I then cleaned the bore in the head out with solvent and a rod I made similar to one for cleaning shotguns with a patch. I scrubbed it really clean (multiple times) so the silicone would stick, finally wiping with dry paper towels. I mounted a new o-ring to the pipe with silicone, slathered on some more silicone (Permatex black label BTW) and shoved it gently back in. I pressed it into the head while my friend struggled to re-tighten the captive bolt. I let the glue set up a while and took a break.

Once the silicone had time to set, I cleaned the end of the coolant hose inside, put some Permatex (orange label) weatherstrip advesive in the end of the hose and clamped it back in place. I let that set up a bit.


Cadd.

[ringadingh]

Its strange that just today I had the LH air filter and fuel tank off and I noticed some antifreeze residue on my #1 Cylinder. Also the wire bracket that supports the air filter housing was cracked and had to be welded. The residue was obviously old and dried on, but I never would have seen it without removing the housing. As soon as it gets a little warmer outside I'll tackle the coolant lines.

[blowndodge]

Jeez MaKaw. Why do you make us find and fix your problems! I'm a knucklehead but I can tell when I see a weak design. those heads should have the intake built into them like cars so we don't have a metal "tweak pipe" leaking. This is why I disagree about our bikes coolant system was designed from the ground up! Oh well. I love her just the same.....

The best thing would be to thread some brass nipples into the heads with thread sealant, instead of the silly tube and o-ring. Unfortunately, I did not want to take a chance of getting metal shavings into that inner pump seal and wrecking it, as that means a complete engine tear down. For this reason I was particularly careful about cleaning off all dirt so it didn't fall inside the cooling system.

The o-rings came from bike-bandit.com BTW.

My bike started seeping coolant withing the first month. The radiator drain bolt was only about finger tight from the factory. (I've checked several of my friend's Vulcans, and every one of them was like that. Plug practically ready to fall out.)

It was also seeping around the coolant hoses. Not fast, just a drip now and then because I never saw it, but could smell it burning off the engine. I tighened all 8 hose clamps, and the smell stopped for about a year (as I recall.) Then it started again.

This time it was the water pump housing gasket. It was still under warranty, but I went and bought a gasket and coolant and fixed it myself. The gasket was from the dealer, and was marked "improved" on the package. It was over $10, and it took the guy a couple tries to find one that wasn't damaged from the parts bin. I shoulda just used silicone. Use silicone on the cover bolts if you gotta do this. One of them is a block drain.

At about the third year I was pretty sure the o-rings were going, as I smelled coolant again. I'd read about this problem on VROC. It's not an expensive fix, and if you are crafty you DO NOT have to remove the fuel injection. The book says you do, but F*** the book. The problem is that the bolt hits the throttle mechanism and won't come all the way out. I just clipped that little tab (It's like 20 gage metal) and bent it a tad, and toko the pipe off. Before I put it back on, I cleaned up the tab and made the little hole into a slot so it drops over the bolt easily if I ever have to take it apart again.

But it will probably never leak. If the surfaces you put it on are really, really clean, and you apply it correctly, it is simply strong as hell. I took great pains cleaning the metal over and over with solvent (SuperTech carb spray, followed by SuperTech brake spray cleaner) before buttering on the glue.

To what part of the pipe did you apply silicone sealant? I would think that you would not apply silicone to the O-Ring.

I applied it to the entire contact area of both the head and the pipe, and the o-ring as well. I cleaned the new o-rings thoroughly beforehand.

I know that some kinds of inferior synthetic rubber do not react well to silicone. (I've seen the actual aging tests, but that's another story...)

Anyhow, I'm hoping that they sold me the best grade of o-rings, which are probably Viton, and about impervious to everything. Or so they say... ::)

The truth is that I could have (and probably should have) left the o-ring off completely. the silicone bond would have been better without it.

[ponch]

Were the O-Rings replacements from Kawasaki? I priced them at Ron Ayers and they are only 59¢ each. The pipes are $9 each. When I do this, I will probably plan it so I can do other things, like put a stebel horn on the bike and put the relay under the tank etc. If I have the $$$, may be an air kit, pipes and get rid of the air injection as well, but then I'd have to get a ECM spoofer...but that is for another day. The "you might as well" train of thought.

[quote:z0r6vr2r]To what part of the pipe did you apply silicone sealant? I would think that you would not apply silicone to the O-Ring.

I applied it to the entire contact area of both the head and the pipe, and the o-ring as well. I cleaned the new o-rings thoroughly beforehand.

I know that some kinds of inferior synthetic rubber do not react well to silicone. (I've seen the actual aging tests, but that's another story...)

Anyhow, I'm hoping that they sold me the best grade of o-rings, which are probably Viton, and about impervious to everything. Or so they say... ::)

The truth is that I could have (and probably should have) left the o-ring off completely. the silicone bond would have been better without it.[/quote:z0r6vr2r]

[ponch]

As an addendum the manual shows that the radiator hoses and O-Rings must (should?) be replaced every 24K miles or 3 years, whichever comes first. That seems excessive, but in light of the O-Ring problem...

Yeah, I'm still running the original hoses, and it'll be 5 years Aug 15th, and probably 33,000 miles. I did buy a spare lower hose, as that's the one seemingly at the most risk. (Close to the exhaust pipe plus exposed to sun.) but the other hoses are pretty well concealed under the tank, and have seemed in A-1 shape each time I checked them. I probably should have just changed the upper 3 hoses when I did the o-rings (hell, all 4 for that matter) but in my book hoses should last 5 years, and I think these will just fine.

Those o-rings, however, are shot after 12,000 miles IMO, and should be replaced after 2 years or less.

Were the O-Rings replacements from Kawasaki? I priced them at Ron Ayers and they are only 59¢ each. The pipes are $9 each. When I do this, I will probably plan it so I can do other things, like put a stebel horn on the bike and put the relay under the tank etc. If I have the $$$, may be an air kit, pipes and get rid of the air injection as well, but then I'd have to get a ECM spoofer...but that is for another day. The "you might as well" train of thought.

They were Kawasaki OEM parts, but I got them at bikebandit.com. They came in a Kawasaki bag, with Kawasaki logo & P/N on it so I asume they were genuine Kawasaki.

[ells]

Thanks for all this good information. Sounds like something to stay on top of. Couple questions maybe someone could answer:

About how many shop hours (dealer or indie) would be involved with replacing the o-rings, with and with/out trying to seal with silicone?

What would be the pros and cons of addressing such a seeping with something like Stop Leak? Actually, isn't there something like Stop Leak in some anit-freezes?

Thanks.