1100 Overheating at Idle

schlep1967 said:
This is good info but the easiest way to tell if the fan is operational is to ensure there is antifreeze in the radiator then run the bike up to temp. If the fan runs you do not have to go through all the trouble shooting as the trouble was lack of coolant. If the coolant is low you are then trouble shooting how you lost coolant. And the common culprit is the overflow hose.
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let's compare the two options:

To jumper the fan wire to ground you need to take off the left side access panel, which has two screws, and you're done.

vs.

checking the coolant level requires:

1. remove both saddlebags
2. remove seat
3. remove both sidecovers
4. remove top shelter
5. remove right access cover to get to screws so you can
6. remove right glovebox panel and finally open the radiator cap to check the coolant level.
I think at this point you've already removed at least 14 screws
7. then wait for the engine to warm up (if its not already hot) and make sure it doesn't overheat when the fan doesn't come on (if that is the case)

If you ask me, the first method is easier than the second
 
dwalby said:
let's compare the two options:

To jumper the fan wire to ground you need to take off the left side access panel, which has two screws, and you're done.

vs.

checking the coolant level requires:

1. remove both saddlebags
2. remove seat
3. remove both sidecovers
4. remove top shelter
5. remove right access cover to get to screws so you can
6. remove right glovebox panel and finally open the radiator cap to check the coolant level.
I think at this point you've already removed at least 14 screws
7. then wait for the engine to warm up (if its not already hot) and make sure it doesn't overheat when the fan doesn't come on (if that is the case)

If you ask me, the first method is easier than the second
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Yep. It is easier. And it will tell you if the fan is operational. But it will not tell you if the system that turns the fan on is operational. That system will not work unless you have coolant in the radiator. So he can test the fan and say "yes it works" and go ride the bike with no coolant in it? Or he can take 10 minutes and remove the plastic so he can verify there is coolant in the radiator. IF there is coolant filled to the top of the radiator then he would know he has either a fan issue or a sensor issue. If the coolant is low he can top it off and figure out how he is losing coolant.

To the original poster, it is obvious there are different ways to go about this. From your post is seems you are willing to check out the whole system. To do that you are removing plastic anyhow. This system will give you varying symptoms if the fluid is low. One of those symptoms is fan failure (actually not failing just failing to be turned on) due to the temp sensor being above the low fluid (as others have said in this thread). Without a full radiator you will be fixing symptoms, not the cause of those symptoms.
 
schlep1967 said:
Yep. It is easier. And it will tell you if the fan is operational. But it will not tell you if the system that turns the fan on is operational. That system will not work unless you have coolant in the radiator. So he can test the fan and say "yes it works" and go ride the bike with no coolant in it?
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If you go back to my original post you will see that checking the fan operation was the first of four steps, it was not the only step. If the fan didn't work, then he can trace out the wiring issue, or easily drain the radiator if he wants to remove the sensor for additional testing, because this step can be done with the bike cold. Then read my post again and notice that step 2 is not "ride bike", its check the coolant level, just as you have suggested.
 
Thanks for all the help guys, I wasn't able to determine if the fan was running before tearing into it, but now that I've done that I found that the fan is running, the coolant is at proper level, so what's next? The thermostat? Like I said it doesn't overheat while riding or even in traffic, only when I let it idle too long. If it is the thermostat, how do I get to the bolts in front that hold the thermostat housing in? Does the front plastic need to come off from around the headlight/windshield, I can see straight down on the radiator cap and thermostat housing but with the plastic that I have off, I still can't access the bolts from the front that hold the thermostat housing in.
 
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bradwilder1 said:
Thanks for all the help guys, I wasn't able to determine if the fan was running before tearing into it, but now that I've done that I found that the fan is running, the coolant is at proper level, so what's next? The thermostat? Like I said it doesn't overheat while riding or even in traffic, only when I let it idle too long. If it is the thermostat, how do I get to the bolts in front that hold the thermostat housing in? Does the front plastic need to come off from around the headlight/windshield, I can see straight down on the radiator cap and thermostat housing but with the plastic that I have off, I still can't access the bolts from the front that hold the thermostat housing in.
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OK, so the fan works when you jumper it, but still doesn't come on as the temp needle rises into the upper range, right?

Logically, I'd have to say that if your stat was stuck closed, then having the bike moving vs. being stopped wouldn't make much if any difference, because the coolant isn't getting into the radiator anyway. Or perhaps having the engine running at speed turns the water pump fast enough to force coolant past the stuck stat, but at idle it doesn't have enough force.

At this point its easy to replace the stat. Look just next to the rad cap and you'll see a black plastic shroud in front of the stat housing. The screw to remove that is on the top of that shroud. Pull the shroud out and you'll see the bolts for the stat housing if you look back from the front of the stat with a mirror. Can't remember if there's 2 or 3. Pull those out and the stat is inside the housing, but you'll probably need a new O-ring for the housing, so have one ready before you tear it apart.

If its not the stat then the next suspect is the thermo switch itself, and that's easy to remove once you drain the coolant.
 
Well what's next needs to be checking the stat for the fan that you pulled the wire off to test the fan.....

This will require a partial drain down before removing.

To my mind if you are going to do this then you may as well get that plastic off, change the thermostat, and change the fan sensor as well. It is unlikely to be the thermostat as they normally fail open and you would be overheating a lot more if it was failed shut....

So the fan sensor seems the likely culprit.
 
bradwilder1 said:
Thanks for all the help guys, I wasn't able to determine if the fan was running before tearing into it, but now that I've done that I found that the fan is running, the coolant is at proper level, so what's next? The thermostat? Like I said it doesn't overheat while riding or even in traffic, only when I let it idle too long. If it is the thermostat, how do I get to the bolts in front that hold the thermostat housing in? Does the front plastic need to come off from around the headlight/windshield, I can see straight down on the radiator cap and thermostat housing but with the plastic that I have off, I still can't access the bolts from the front that hold the thermostat housing in.
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I have noted that we have never, in all of Brad's posts here, actually established whether the fan WAS working during the periods of overheating in traffic. It may well have been and inexperienced Brad was not aware of it. It may be that what Brad perceived as overheating from his temperature gauge has actually been what many of us has seen during heavy traffic speeds. The gauge did not go into the red, so what level did it actually reach, since we all have experienced the gauge needle reading at least straight up, or even slightly more to the red, before you hear the fan come on.

Thermostats can seize in a partially open manner also and it might be possible the restriction will reduce the rad flow, made more noticeable in idling traffic.

I just question IF there is indeed a real problem here, which is something a good observational test ride would resolve.
 
he said it was way to the right, almost into the red, which sounds higher than it should be if the fan is working normally and the radiator is full.

This doesn't sound like the normal straight up or just a little past straight up if things are working reasonably well.


Yikes, I just realized this sounds like my bike was acting before I realized I had rusted away the water pump impellers due to lack of coolant maintenance. At speed the pump could move enough water, at idle it was struggling, sometimes it would kick on the fan, other times not. But it didn't ever go into full overheat mode into the red, it always seemed to work its way down eventually, but I never sat idling very long. Since he just bought the bike he has no idea if the PO abused the coolant like I did.

A new stat made my problem seem to get a little bit better, but not by much. After I replaced the water pump is when the big difference happened.
 
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So from the electrical side and mechanically the fan works; motor is OK, no bearing failing, propeller firmly attached to the shaft (there were cases where the shaft slipped inside the center attachment, giving the impression of proper functionality, but in real the actual airflow was way too low...), not obstructed by anything that had fallen down there and is now sitting between a prop blade and the radiator (popular are the rubber well-nuts fixing the windscreen and garnish plate...)
Coolant in the radiator is topped off, no obvious leaks of the system visual
Under these conditions the fan must kick in when the gauge needle hits a 1210 o'clock position... if not, something is off...
The fan/stat can easily be removed an tested by throwing it into a small pot with water on the stove: its a 100?C ON device, so once the water starts to boil, it'll close... (one could also use a heat-gun and IR-thermometer if avail...)
It could as well be replaced right away, its a cheap standard part, also found in Civics, Accuras or Honda gardening equipment...

If that all turns out OK, not much suspicious left: obstructed or insufficient coolant flow

Failing coolant stats normally stuck in OPEN... easy to check by removing the filler cap on a still cold, idling engine: lots of coolant flushing indicates a stuck/open thermostat...

If that also turns out OK, the ducts of the radiator could be squeezed shut due corrosion (actually rare and would rather show by increasing temp under full load -> much fuel being burned), or the coolant flow is obstructed otherwise.... like the blades of the pump impeller have corroded away....
 
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