Coolant leak

[Kool_Biker]

Hello everyone,
I'm in the process of recommissioning my K1 GL1000 and with carbs out, noticed a small coolant leak as shown in the picture below. The leak is, for sure, from the area circled in red (feels wet).
HOWEVER, following a 15 psi pressure test of the cooling system, I could not make it leak any further nor loose any pressure.
Any ideas? Should I remove the entire assembly, thermostat and all, clean, change all o-rings etc?
Many thanks
Aris

[pjlogue]

I would replace the gasket or O ring. These types of leaks usually will get worse over time and unfortunately tend to completely fail at the worst time.

With these old bikes a lot of times the mating surfaces are nicked up or corroded. I will hone flat surfaces with 600 emery paper on a flat backing surface to remove all old gasket and minor nicks/scratches. Inside surfaces (like the coolant line tube receiver) I'll take 600 emery and run it around the inside to clean it. All O rings get a light wipe down with Dow Corning Vacuum grease, groves get absolutely cleaned out. Never had a leak come back doing it this way. The vacuum grease allows the O rings to move and seat properly when assembling parts.

-P.

[rcmatt007]

I have seen that kind of leak which seems to happen at cool down, but when the bike is up and running, no leak. I agree with what PJ says, in that it is usually an old O-ring or some small corrosion on the mating surface

[Kool_Biker]

Thank you for your inputs.
Clearly, avoiding fixing this problem now will only lead to a much bigger one down the line.
I do not look forward grappling with these old bolts, dreading not to break any. But there we are.
Cheers,
Aris

[77Gowing]

Good luck Aris & Yasoo!

[pjlogue]

It's a good idea to soak any bolts with PB blaster for several days before trying to take the bolts out. Spray some each day and if you can get to the back side of a through hole bolt spray it as well. This will greatly lessen the chance of snapping off a bolt. Also, don't use a 12 point socket/wrench on stuck bolts!

-P.

[ericheath]

Are you sure it’s not the rad hose leaking and trailing down?

[Kool_Biker]

Yes, the leak is certainly coming from where shown in the original pic. Also, I am subjecting all relevant bolts to numerous heat / cool cycles with oodles of Kroil in between. So far 3 have come out without undue drama, and I continue. Patience is my friend. But I have to say accessibility to this part of the bike is awful due to the big shroud over the assembly in question.

Many thanks to all!
Aris

[pidjones]

The shroud can be removed (or at least unbolted and moved out of the way) as long as the front lower bolt is in. Just don't forget how the stays and washers go on it. You might also try tapping on the bolt heads to free them up. I've been lucky with the bolts into the block, but had one into a head break (luckily with plenty left to grab with vice grips) and one pre-broken by a PO that came out easy, too. Clean all o-ring surfaces to very smooth and lubricate all o-rings with Dow High Vacuum Grease to prevent pinching and allow them to squirm around to seat. In the culprit joint, as I remember that o-ring goes around a tube that fits down into the head recess. Make sure the old o-ring is out (use care to not gouge a surface while getting it out!) and clean extra-well. Many will say to replace the thermostat while you have that out, but beware that the o-ring for it does not come with the part. Also, this is NOT a good place for Viton! These joints expand and contract a bit, and Viton is not known for resilience that nitrile (Buna=N) has.

[Kool_Biker]

Gotcha!
I have finally managed to get to the problem area, without snapping any bolts or unduly stressing anything.
And glad I did, as I am sure you will agree from the pictures, there's trouble there.
I've already got all replacement O-rings, original Honda.
Unfortunately though, the rusty 12X10 collar (P/N 90701-371-000) is NLA .
I guess I could make one, or better still, modify one from Honda which might be same diameter, only longer. Does anyone know of such a part number?

Many thanks again for all your support and guidance. Much appreciated.

[rcmatt007]

clean it up with some 1000 grit paper?

[pidjones]

Congrats on a drama-free disassembly! Looks like what Honda calls a "dowel", which are still available although I don't know if that length is. IF you can get it out, spin it with a lathe or drill and shine it up, put it back in.

[rcmatt007]

Congrats on a drama-free disassembly! Looks like what Honda calls a "dowel", which are still available although I don't know if that length is. IF you can get it out, spin it with a lathe or drill and shine it up, put it back in.

yeah.... what he said just don't bend it

[pjlogue]

If the dowel pin is stuck put a butt end of a drill bit that will just fit into the dowel and wiggle it back and forth to loosen it. It should come out fairly easily then. Penetrating oil will help. I suggest you get a new dowel and carefully clean the mating surface and O ring grove. A small bit of coolant ATV sealant on the new O ring will ensure a leak free seal upon reassembly.

-P.

[robin1731]

I wouldn't go through the hassle of getting that dowel out. As suggested earlier just clean it up and leave it. Also clean up the area in the housing that goes over the dowel. Too much chance of causing more problems than it's worth trying to get it out.

.