Water Pump or Thermostat???

[wilcoy02]

Was looking to change the anti freeze on my GL1100. Had the engine running for 15 mins or so. The fan came on and temp gauge half way up.

I had the radiator cap off and watched the water in the neck of radiator. It never circulated.
Do I have a thermostat problem or do I have a water pump problem? How do I check ?

I really do not want to tear into the radiator.

 

[Dusterdude]

You can take the stat out and run it to see if you have circulation

Sent from my LM-X420 using Tapatalk

 

[wilcoy02]

Thanks Dusterdude. Not what I wanted to hear. I only wanted to change the anti freeze not do a whole new project.

Any other suggestions.

 

[saganaga]

To test for circulation, keep the radiator cap off, wait for the engine to warm up slightly. Then rev the engine briefly - water level should drop.

If it isn't circulating, I'd suspect thermostat, and here's my reasoning: The Goldwing waterpump is dirt simple - an impeller on a shaft with some bearings and seals to protect the bearings. When a water pump fails, the typical failure mode is a seal, usually the one on the coolant side of things, exposing the bearings to water.

Now, in theory, the impeller could fall off or the shaft break, but I can't imagine that to be a common failure mode.

But you can test both. To check the water pump, drain the coolant, take the water pump cover off (two bolts, o-ring behind it), then see if the impeller is attached to the shaft. To check the thermostat, drain the coolant, remove the radiator, then the thermostat. Toss the thermostat in a pot of boiling water - it should open.

Technically according to the service manual it should start to open at 176 - 190F, and be fully open at 194F. So to be accurate, you could fly to Denver and climb a 10,000ft mountain and boil water there to test. Or you could use a thermometer.

 

[wilcoy02]

Well Thank You for supporting my suspicions. Some how I knew I'd have another project to contend with. I know that is why I do not like maintenance. Always find something that needs fixin during riding season.

 

[desertrefugee]

Either job could be done in a day. Both in a weekend. Barely a dent in the riding season.

 

[mcgovern61]

You said the fan came on and the temp gauge was at half?. Did the fan shut off? Did the temp gauge keep rising?

If the thermostat was stuck, the temperature would continue to rise and not stop halfway.

If the waterpump was not working, the temperature would rise and not stop halfway.

I suggest you try the previously suggested tasks; start the engine, run with the radiator cap off, let the temperature rise until the fan comes on (takes almost twice as long when the radiator cap is off because you cannot build any pressure and the engine is not under a load). When the fan comes on and the temp gauge rises, raise the RPM's in quick bursts while looking into the radiator fill tube. The antifreeze should drop a bit. You will not see circulation if the radiator is filled to the top.

Again, unless the engine is overheating (temp gauge rises to the hot level and keeps going) I do not believe you have any actual problem.

 

[wilcoy02]

I have done as you said. When I revved the engine the water never moved. It never went down. That is when I wondered if I have a problem or not.

 

[dan filipi]

Sounds to me like it's all working as it should since temp rises and fan turns on. As long as it doesn't get hot beyond normal conditions.

 

[Ansimp]

If you can get access to an infrared heat gun you can take readings off the radiator tanks and get a reasonable base line. There is only about 5-10C variance between actual coolant temp and scanned temps. The 10 degree variance was on the radiator fins (hottest reading) and it always gets cooler when getting closer to the outlet/return pipe.