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Discussion Starter · #1 ·
Well, the day started off around 7:00am with an oil change, final drive oil change, and a coolant exchange. All was going well until I got back from a short ride. I got off the bike and let it run for a few more minutes to ensure I wasn't purging any fluid anywhere. Then, my temperature light came on.

This is the first time that I have exchanged the coolant in the bike. I have no idea when the previous owner did this----or if he ever did this. I followed the Honda Service manual to the tee in this procedure.

I shut the bike off and let it sit for a few minutes, then I started her back up. She ran as she should until the fan kicked on. Once the fan fired up, the temperature light came back on.

Any ideas here? Could this be a thermostat issue? Or am I missing something obvious. Thanks to all!

By the way, 1998 VT1100C Aero
 

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I am just about to change my coolant too...so I am eager to see how this turns out.

Jim
 

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Discussion Starter · #3 ·
Overall, the process was fairly easy. I have read many posts on here about coolant exchanges. I just busted out the Honda Service manual and followed the directions. Good luck!
 

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Discussion Starter · #4 ·
In addition, I have never had any problems with the bike overheating. The idiot light has never come on. It was just time to do routine maintenance and this time that included the coolant.

There is no coolant boiling out of the radiator itself and there are no leaks coming from anywhere that I can tell. Frustrating.
 

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It sounds like you had an air bubble in the system when you refilled it.
Let the bike cool down completely and remove the system cap and check the level. It shouldn't have any air in there. If the fluid isn't at the top, top her off.

With a full purge this can take a few cycles for the system to stabilize. Make sure to check the reservior after a ride to check the hot level. If coolant isn't at the hot level when the bike is fresh from a ride, fill it to the proper line.

Some people don't know this but the cooling systems breathe. When the bike is warm it will expel a small amount of coolant into the reservoir. When it cools down it will suck coolant out of the reservoir. If the reservoir is ever empty when the bike is hot (after a ride) then when the bike cools down it will introduce air into the cooing system. Air is bad for the cooling system as it compresses and allows/encourages boiling. Boiling is BAD for the system as the air pockets from the boil will get into the water pump area and thermostat and that will cause a malfunction in the circulation which, in turn, causes more breakdown.

So, make sure there's no air in there.
 

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Discussion Starter · #6 ·
Thanks for the info Inferno. When you say remove the system cap, you mean the actual radiator cap right? Not the reservoir cap? I'm just making sure. I figure here is as good a place to ask dumb questions as any.
 

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Thanks for the info Inferno. When you say remove the system cap, you mean the actual radiator cap right? Not the reservoir cap? I'm just making sure. I figure here is as good a place to ask dumb questions as any.
Yes, the radiator cap.

And remember, the dumbest question is the one you should have asked but didn't.
 

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Yup the radiator cap. Always fill / top off the system through the radiator. Good to have the bike running and give it a few throttle blips to help burb the system as you top it off. Always good to have some rags around during this process. Only put fluid in the reservoir to keep that plastic tank between the hot and cold mark. Inferno did a great job of explanation!

Dave
 

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yes, the radiator cap. I had this problem the first time I changed the coolant. It isn't as quick as changing in a car or as tolerant of air. It sure sounds like air. Now that it has run a while take the cap off (when cool) and it should be full to the top. and do make sure to have the reservoir to the hot mark.
 

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Discussion Starter · #10 ·
Thanks everyone. I think you all were right. I let her cool down, popped the top on the radiator, and sure enough----it was not filled to the top. After topping her off and letting her get to normal operating temperature, all seems to be fine. The fan kicked on as it should. This time, no idiot light to scare the bejeezus out of me.

Thanks again for all that this forum does. I am not so sure that I've ever run into a group of more knowledgeable folks. Have a good weekend all.
 

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There is a lot of info here, anytime I need to know something I do a search and bam, there it is.
 

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1. Make sure you double click the cap.

2. I always put a hemostat on the overflow tube just above the reserve tank so it also fills up, then unclamp after installing the radiator cap. This makes it a 'closed' system with no air masses and no overflowing out the reserve.
 
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