coolant seems pressurized after sitting


Information and questions on GL1100 Goldwings (1980-1983)
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GEHines2010
Posts: 8
Joined: Tue Oct 05, 2010 7:17 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1983 GL1100 Aspencade

coolant seems pressurized after sitting

Postby GEHines2010 » Thu Apr 25, 2013 11:25 am



I had my 1938 Honda GL1100 (Interstate) in storage over the winter (5 months). I started it about once a month and let it run till the fan came on. A couple of weekends ago I was working on trying to lube the center stand when I noticed a few drops of coolant on the floor. I looked closer and saw some coolant on top of the engine also. I hadn't started the bike for maybe a month at this point. Took the false gas tank off and removed the radiator cap to have a look. When I removed the cap coolent spilled out on the floor. I'm wondering why it seemed to have that kind pressure in it. The stuff that I saw on the floor and on top of the engine somehow came out through the cap I guess. Maybe I need a new rubber gasket?

A friend said that the coolant being pressurized like that when the bike has not been started for a long time could indicate a leaky head gasket.

Since then I taken it on some good runs, probable 500 plus km, and had no problems with overheating. The needle on the temp guage stays right where it should be, the fan isn't on, it takes the same amount of time to warm up. I don't see any evidence of milky oil when I look in the sight glass, so I sure hope my friend is wrong.

Any thoughts.



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WingAdmin
Site Admin
Posts: 17050
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: coolant seems pressurized after sitting

Postby WingAdmin » Thu Apr 25, 2013 7:29 pm

First off, you really shouldn't start it during storage, unless you can get it out and ride it. Letting it sit and idle doesn't get the exhaust hot enough to evaporate moisture (which is a byproduct of combustion), and the end result is that your exhaust stays wet and rots out from the inside. Just let it sit and sleep all winter.

Here's my guess on your coolant situation - although it is just a guess. If the bike got very cold, the coolant contracted, sucking up some coolant from the reservoir. When it got warmer, the coolant expanded, pressurizing the coolant system like it is designed to. The radiator cap will only let coolant pass into the reservoir tank at a certain pressure. Normally what happens is, when the bike is run, the coolant gets very hot and expands a lot, until it reaches the pressure limit of the cap, at which point it overflows into the reservoir. When you shut down, it cools off, contracts, and sucks it back from the reservoir. So if it was warmer than it had been, the coolant could expand, but not enough to pass the cap's pressure limit.

If you don't see any more leaking, and the cooling system is running fine, then I wouldn't worry about it.

User avatar
WingAdmin
Site Admin
Posts: 17050
Joined: Fri Oct 03, 2008 4:16 pm
Location: Strongsville, OH
Motorcycle: 2000 GL1500 SE
1982 GL1100A Aspencade (sold)
1989 PC800 (wife's!)
1998 XV250 Virago (sold)
2007 Aspen Sentry Trailer

Re: coolant seems pressurized after sitting

Postby WingAdmin » Thu Apr 25, 2013 7:29 pm

WingAdmin wrote:First off, you really shouldn't start it during storage, unless you can get it out and ride it. Letting it sit and idle doesn't get the exhaust hot enough to evaporate moisture (which is a byproduct of combustion), and the end result is that your exhaust stays wet and rots out from the inside. Just let it sit and sleep all winter.

Here's my guess on your coolant situation - although it is just a guess. If the bike got very cold, the coolant contracted, sucking up some coolant from the reservoir. When it got warmer, the coolant expanded, pressurizing the coolant system like it is designed to. The radiator cap will only let coolant pass into the reservoir tank at a certain pressure. Normally what happens is, when the bike is run, the coolant gets very hot and expands a lot, until it reaches the pressure limit of the cap, at which point it overflows into the reservoir. When you shut down, it cools off, contracts, and sucks it back from the reservoir. So if it was warmer than it had been, the coolant could expand, but not enough to pass the cap's pressure limit.

Is it possible the rubber hose between the cap and the reservoir is leaking? Or the reservoir itself?

If you don't see any more leaking, and the cooling system is running fine, then I wouldn't worry about it.

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1fastgl1100
Posts: 131
Joined: Mon Apr 22, 2013 5:33 pm
Location: Ocala, Florida
Motorcycle: 1983 GL1100A and 1982 GL1100A Modified

Re: coolant seems pressurized after sitting

Postby 1fastgl1100 » Fri Apr 26, 2013 12:15 pm

my concern is where did you get a 1938 goldwing?

GEHines2010
Posts: 8
Joined: Tue Oct 05, 2010 7:17 pm
Location: Victoria, British Columbia, Canada
Motorcycle: 1983 GL1100 Aspencade

Re: coolant seems pressurized after sitting

Postby GEHines2010 » Fri Apr 26, 2013 9:01 pm

Whoops on the date, thanks alot on the input. Haven't seen anymore leaks at all, so good!




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