gl1200ltd boiling over


Information and questions on GL1200 Goldwings (1984-1987)
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ezrider354
Posts: 4
Joined: Sun Aug 03, 2014 2:54 pm
Location: Howell, MI
Motorcycle: Gl1200ltd

gl1200ltd boiling over

Postby ezrider354 » Sat Aug 23, 2014 7:29 pm



I just revived a 85 ltd after sitting in a barn for 16 years. Ive done all the prerequisites to get her on the road and she is beautiful. She shows 21000 miles and we have put about 500 trouble free miles on her. Ecept for one issue. When idling it will blow coolant/steam out of the overflow tube under the bike. I have already installed a new waterpump and aftermarket thermostat. The fan comes on as it should, however it turns off, then it starts to spit. If I turn off the ignition then turn it back on the fan comes on again without starting the bike as it continues to boil over. It only does this while stationary. If the bike is moving no issues at all.



User avatar
HawkeyeGL1200
Posts: 918
Joined: Sat Jul 05, 2014 11:53 am
Location: Courtland, Va.
Motorcycle: 1984 GL1200 Interstate
1981 GL1100 Interstate

Re: gl1200ltd boiling over

Postby HawkeyeGL1200 » Sat Aug 23, 2014 7:57 pm

Assuming the radiator is clean, inside and out, the only questions I have is have you looked at the condition of the radiator cap and the hose from the cap to the overflow reservoir? A bad cap can effect the pressure inside the coolant system, and can cause the condition you describe. One reason our cooling systems work as they do is the increase in pressure in the system. A cap that won't maintain pressurization of the cooling system won't allow it to function normally. A hose that doesn't direct coolant from the cooling system to the overflow will allow the cooling system to pull air into the coolant, which will also cause it to work improperly. To operate correctly, the system should be "solid" with no air in it. The reservoir allows the expanding liquid to be discharged from the system to the overflow, and then as the system cools down again, coolant to return to the system without the inclusion of air.

Trash accumulation on the inside or outside of the cooling fins of the radiator can contribute to your troubles. Some condenser coil cleaner, like the kind used for HVAC coils is an effective way to clean the outside of a radiator. Soap and water work pretty good too, if you can deliver them with a little gusto.

The only other thing that comes to mind is the possibility of some blockage of air flow behind the radiator, which I figure you've already checked into having changed the water pump and thermostat. I guess it is also possible the fan switch is wonky and it is allowing the fan to turn off before it has cooled the engine sufficiently. I'd check cap, overflow tube from cap to reservoir and the switch after verifying the radiator is clean as it should be.
I am wrong as often as I am right concerning what is wrong with someone else' motorcycle without having seen the machine in person. Guessing with limited information, as to the source of the trouble, is sketchy at best.

ezrider354
Posts: 4
Joined: Sun Aug 03, 2014 2:54 pm
Location: Howell, MI
Motorcycle: Gl1200ltd

Re: gl1200ltd boiling over

Postby ezrider354 » Mon Aug 25, 2014 9:23 pm

Today I tested the cap it holds 9psi. I tried to get a new cap but ended up with the wrong one. I need a part# for a cap that will work. I tkink the new thermostat might be bad but would like to try a cap first. All the hoses are in good shape and the radiator is clean in and out. Is there a bleeding procedure for the cooling system or just fill, run and top off?

ezrider354
Posts: 4
Joined: Sun Aug 03, 2014 2:54 pm
Location: Howell, MI
Motorcycle: Gl1200ltd

Re: gl1200ltd boiling over

Postby ezrider354 » Tue Aug 26, 2014 8:45 pm

New cap from advanced auto, 6.99 now no more issues.

User avatar
HawkeyeGL1200
Posts: 918
Joined: Sat Jul 05, 2014 11:53 am
Location: Courtland, Va.
Motorcycle: 1984 GL1200 Interstate
1981 GL1100 Interstate

Re: gl1200ltd boiling over

Postby HawkeyeGL1200 » Tue Aug 26, 2014 9:11 pm

Good to read it was a simple repair.


I am wrong as often as I am right concerning what is wrong with someone else' motorcycle without having seen the machine in person. Guessing with limited information, as to the source of the trouble, is sketchy at best.


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