Honda Shadow ACE - temp light on

[murphyslaw1978]

Anyone familiar with the 1995 Honda Shadow ACE? My temp light came on briefly for the fist time in 2 years. I changed the cooling fluid a few months ago, but don't think that is the problem. I suspect that the fan is not coming on. I plan on running 12V to the fan to see if it spins, but is there an easy way to test the temp switch on the radiator or fan before I start pulling things apart? These connections are not that easy to get to.

BTW, I think I have a good water pump because the temp light won't come on while driving. Only when stopped. Also, the radiator is nice and hot, indication that I'm getting circulation and fluid moving around.

[DrBob]

You should be able to hear the fan kick on at stoplights, etc.. Start the bike and let it idle for about 10 minutes. The fan should come on briefly once the bike gets hot, then cycle on and off as needed. If it doesn't, chances are you need the temp sensor that controls it, as this is by far the most common point of failure in the system.

[Easy Rider]

Originally Posted by DrBob

as this is by far the most common point of failure in the system.

Actually it's second on the list.
Comes right after: Operator changed coolant and didn't get the system full again (or didn't get all the air out).

[murphyslaw1978]

Originally Posted by DrBob

You should be able to hear the fan kick on at stoplights, etc.. Start the bike and let it idle for about 10 minutes. The fan should come on briefly once the bike gets hot, then cycle on and off as needed. If it doesn't, chances are you need the temp sensor that controls it, as this is by far the most common point of failure in the system.

I started the bike yesterday and ran it for about 10 minutes. Then I let it idle for another 10 minutes - the light or fan never came on. I'll check the coolant level first, then apply 12V to the fan. If the fan comes on and I've got full coolant, then I think it might be the switch.

I think replacing the switch will result in draining the coolant from the bike??

[murphyslaw1978]

Originally Posted by Easy Rider

Actually it's second on the list.
Comes right after: Operator changed coolant and didn't get the system full again (or didn't get all the air out).

The process I used to flush the coolant I used was this:

1.) Pull the drain and release the fill cap when cold.
2.) Only about 2 quarts of fluid came out
3.) I used a water hose to flush at least 1 gallon of water through the engine
4.) I used a 50% mixture of lifetime orange Prestone and water
5.) I started the engine, ran it for about 2 minutes and checked the level. I added about 6 more oz to the radiator
6.) I then filled up the reservoir
7.) Since then, I've driven about 400 miles without any issue. The temp light only came on for the first time at the end of a 320-mile trip.

[Easy Rider]

Originally Posted by murphyslaw1978

The process I used to flush the coolant I used was this:

7.) Since then, I've driven about 400 miles without any issue. The temp light only came on for the first time at the end of a 320-mile trip.

The proceedure looks good to me.......except that now you need to check the levels again, both in the overflow bottle AND the actual radiator.
OR
If the level in the overflow has dropped a little bit (when cold), then everything is probably OK and you just need to add to the overflow until the level stabilizes. This is pretty much normal; blows out excess air as it heats up and sucks water back in from the bottle as it cools.

[DrBob]

If I recall correctly the sensor is at the top of the radiator, so there is minimum coolant loss when you remove it. Pre mix a little and put it in a sport bottle, and squirt some back in to top it off.

[murphyslaw1978]

Update: I drove my bike on the highway for about 20 miles and then through some city streets. The temp light never came on, but when I shutdown, I heard burbling noises coming from the engine. Sounded like something was boiling.

So now it would appear that I did not correctly scavenge all the air bubbles when I refilled, so I will check that again.

Is there a way to all the air out of the system easily?

[Easy Rider]

Originally Posted by murphyslaw1978

So now it would appear that I did not correctly scavenge all the air bubbles when I refilled, so I will check that again.

Is there a way to all the air out of the system easily?

Yes! Let the valve in the cap and the overflow bottle do it for you.

Otherwise, it depends on the specific bike and I'm not familiar with yours. In general, all you can do is be sure it is full to the point of overflowing while warm (not HOT) and running. This can be a little tricky if you have to remove the tank to get at the cap but there should be enough gas in the bowls for a few minutes.

At this point, I would let it go and watch that overflow level.

[murphyslaw1978]

Originally Posted by Easy Rider

Yes! Let the valve in the cap and the overflow bottle do it for you.

Otherwise, it depends on the specific bike and I'm not familiar with yours. In general, all you can do is be sure it is full to the point of overflowing while warm (not HOT) and running. This can be a little tricky if you have to remove the tank to get at the cap but there should be enough gas in the bowls for a few minutes.

At this point, I would let it go and watch that overflow level.

Thanks. I'm such a beginner

[murphyslaw1978]

Well, that resolved my problem. I pulled the fill cap loose and then opened the reservoir cap. The reservoir was completely empty, so I put a 50/50 mixture and filled it up. I started the bike and let it warm up. Then tightened both caps and ran it on the expressway for about 20 miles. Looks like my temp light never came on, but the fan did come on at the end of the trip when I pulled into the garage. It's running as it should.

Thanks to everyone for the good advice.

[Easy Rider]

Originally Posted by murphyslaw1978

Thanks to everyone for the good advice.

Go ILLINI

[murphyslaw1978]

Turns out that my light is coming on again sporadically. I have since driven about 3000 miles. I think that the coolant is evaporating out, because from the expansion tube, I can see puffs of steam coming out slowly.

I never had this problem before changing the coolant, so I think it has to do with that. Maybe I didn't get all the air out of the system, or maybe I used to wrong coolant, but this is getting old. I might just take the bike in a have a pro do it.

Anyone else familiar with this model of bike?