1980 Goldwing GL1100 Overheating

Information and questions on GL1100 Goldwings (1980-1983)
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Location: Denver, Colorado
Motorcycle: 1982 GL1100 Aspencade

1980 Goldwing GL1100 Overheating

Postby echinus1988 » Sun Mar 13, 2016 7:02 pm

Hi everyone,

I am just looking for an opinion that does or does not back up my son's suspicion.

My 1980 GL1100 is running much cooler but still overheats. We've had some warm days but once the temperature climbs it's hard to get back down even moving.

What have I done:
1. Run radiator cleaner through the system. No change seen, the bike was still over heating a lot.
2. Replaced the radiator when I found one that was clean without the build up I had. This helped a lot, the bike is slower to heat up but go up an incline at 65-70 mph and the bikes starts heating up. I usually turn on the fan at about 1/2 way up the gauge. I installed a manual switch because the thermostat switch is not working.
3. Replaced the thermostat with a new one from NAPA. Can't recall the model but it was the one recommended by the article here with cross reference numbers.
4. Replaced the stock plastic bladed water pump with the metal bladed water pump.
5. Running the fan will bring the temperature down slowly. A little faster when I am actually moving but staying below about 55.

In a nutshell, I haven't been in really warm temperatures but we have hit the high 60s to low 70s. Riding at under 65 on level, the temperature will go up but not quite to halfway. Going up a hill it gets halfway or higher until I lose my nerve and start the fan. Sitting in traffic I will heat up almost to the red (and would go into it if I didn't start the fan).Flat and level ground above 65 will generally cause the engine to really heat up in the mid to higher range. I got a lot of improvement when I changed the radiator.

I tested the old thermostat and in boiling water it definitely opens up. I just don't know how much it should open, I guesstimate it opens about 3/16-1/4". Is that enough open to allow coolant to flow like it should and cool properly. Could my new thermostat be stuck in a partially open position allowing coolant to flow but not enough to allow the engine to cool properly? How far should a thermostat open to be effective? Should it drop almost all the way down and compress the spring tight? Is there somewhere I can find photos or the correct opening?

I am preparing to pull the thermostat to test and see what it does. If it opens, what else can I check.

Oh, my son is convinced that it's a thermostat that won't open all the way. Just enough to allow coolant through and allow some cooling to take place.

As always, thank you for your help.

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84 GL 1200 I

Re: 1980 Goldwing GL1100 Overheating

Postby virgilmobile » Sun Mar 13, 2016 9:25 pm

You may be guessing about the temp by what the gauge reads.You can verify operating temp by removing the sending unit...slowly heating it in water with a thermometer next to it and watching the needle position.This is even shown in the service manual.
Or you can shoot a IR to measure the temp.
Keep in mind,this is just like a car cooling system.The thermostat opens and closes to regulate coolant flow (speed) through the radiator.
Most of the time,I find that the needle is just below the red mark when the fan turns on...somewhere about 195°-200°.
A proper operating system,as mine was,rarely approached the red mark above 40 mph.40MPH air flow was always sufficient to cool the system.
One other thing to mention..If you believe you've touched all the possible problems,consider that there may be a bad head gasket.Under stress and heat,it may be leaking exhaust compressed gas into the water jacket.Only increasing the coolant temp as the engine is hot and running at a high rpm.

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Motorcycle: 1982 CX500 Turbo (restoration project)
1981 GL1100 Interstate (sold)
1988 GL1500

Re: 1980 Goldwing GL1100 Overheating

Postby Aussie81Interstate » Mon Mar 14, 2016 2:28 am

I would look at giving the whole system a good check over. Maybe even a new radiator cap.

What sort of coolant are u running through the system? My recent issues with my 1500 have been due to a blocked radiator core - and a bad thermo switch unit. Running on hot days of over 90 degrees and highway cruising of about 65-70 would push the gauge to over halfway - and the bad thermo switch didn't help either. After radiator flushed out - new thermostat, new fresh coolant, and the correct rated thermo switch seems to have solved the problem.

My previous 1100 interstate got new hoses, flushed radiator - new cap and was then all good.

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Motorcycle: 1981 Honda Goldwing Interstate GL1100I
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Re: 1980 Goldwing GL1100 Overheating

Postby sportsfreaked » Tue Mar 15, 2016 8:37 pm

Have the system pressure tested. If the system test ok then I would go the route of the head gasket as well. A leaking head gasket will almost always cause you to overheat. You can have a leaking head gasket and the engine can still seem to run just fine. Let us know what you find out.

Thanks to all who answer and help. It is greatly appreciated!

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