Humm..... Thermostat????

[Slick]

Got caught in bumper to bumper trafic today on Florida's Turnpike coming home from the Leesburg Bikefest. The temp light came on so I pulled off to the side- pulled the fan fuse and it seemed fine (the fan was not running) reinserted the fuse, started the bike and the fan started working. Went a few hundred more feet and the light came back on. Again pulled over to let her cool for about an hour ( was'nt going anywhere anyway). Traffic finally started moving so back on the bike and everything was peachy.

Rode to the next service plaza (bout 40 miles) with no issues. I got off for a break and left the bike running to see what would happen. Fan kicked on and no light- got back on her to finish my trip and as I was about to pull out the light came back on- I got back on the road and after about a minute the light again went off, and stayed off for the remainder of my journey.

Any input here would be helpful-

Thanks,

Slick

[3W-lonerider]

i just replaced my thermostat for that very reason. would over heat in stop and go traffic..also wired in a switch to turn the fan on and let it on till i start moving again. also check the coolent in your radiator. if your cap isn't sealing well enough on the upper gasket it will throw coolent to the reserve resivour even if it does'nt leak out the cap but cannot retreave it back when it needs it because of the cap.

[scoot]

Did you check your coolant level? That would be my guess. The upper hose clamp to the block commonly come loose, and it may be leaking slowly. As long as you are moving it gets enough air to keep it cool. As soon as your not moving it heats up. It usually happens faster then the fan can react. By time the light comes on your already over heated.

[Six Guns]

I did a search and found this post from RP#62. It was the cause of my problem.

The '97-'99 models have an Engine Coolant Temp Indicator Unit between the sensor and the light. On the later models, the sensor was replaced with a thermostatic switch that turns the light on directly. If you've replaced everything else and you still have the problem, barring any wiring or connector problems, its probably the Temp Indicator Unit. Some folks have just got the new sensor (switch) and wired around the Temp Indicator Unit as was done on the later models.

Its listed as 38710-MZ0-003
INDICATOR UNIT, TEMPERATURE (Honda Code 5051974)

#16 in the diagram

[Tundra]

I did a search and found this post from RP#62. It was the cause of my problem.

The '97-'99 models have an Engine Coolant Temp Indicator Unit between the sensor and the light. On the later models, the sensor was replaced with a thermostatic switch that turns the light on directly. If you've replaced everything else and you still have the problem, barring any wiring or connector problems, its probably the Temp Indicator Unit. Some folks have just got the new sensor (switch) and wired around the Temp Indicator Unit as was done on the later models.

Its listed as 38710-MZ0-003
INDICATOR UNIT, TEMPERATURE (Honda Code 5051974)

#16 in the diagram

+1

[Slick]

Thanks for the replys folks.

Anybody have a part # for the thermostat?

I will be checking out all your suggestions tomorrow on my day off. I hope it's simple like low coolant caused by a loose hose clamp or bad seal on the cap, cause I wouldn't even know where to start with the switch thingy- HELP

[Six Guns]

Behind the left side cover. Remove the coolant bottle and you will see it. Release the locking tab and it will unplug. Plug in new Temp. Indicator Unit, replace the coolant bottle and you are done. I promise you, if I can do it anyone can.     

[YoungPUP]

I think theres a parts interchange list in shoptalk that has several p/n's for the thermostat.

[2qmedic]

Perhaps I miss read your initial post, but,
I was under the impression that the temp light was on and the fan was not on... ???
this would indicate wither the fan, curcuit or the switch would be at fault.

[Tropic traveler]

Were there any symptoms of the engine actually running hot or just the temp light coming on??
Plus 1 on checking your coolant level.
Engine may be just fine. Maybe it's all electrical?

[Black Dog]

I think Six Guns has your answer...  My issue was same as yours, and that part fixed the problem.

Black Dog

[Slick]

Thanks again guys- but it appears the answer is stupidity on the owners part.

I have gotten in the habit on my VTX to check the overflow tank, because the radiator cap is under the tank. Well when I T-clocked the Valk before my trip I did the same and it appeared fine. Well when I was going thru the bike yesterday checking all your recommendations, lo and behold I was low on coolant in the radiator. I filled it up and let her idle for 45 minutes and guess what no light- problem solved it seems

Thanks again for the assist-


Slick

[3W-lonerider]

i would keep an eye on that radiator..if your coolant tank had fluid in it and your radiator was low..i'd suspect a bad seal on the cap..what i mean by a bad seal..is when your engine gets hot it will push fluid into the resivour and as your engine cools it will require that fluid back but because it cannot create the vacumm it needs to draw the fluid back into the radiator it stays in the resivour leaving your radiator half full. i had that problem on a long trip. what i done to cure it was bend the tabs on the cap to create a tighter seal..been working fine ever since.

[MP]

i would keep an eye on that radiator..if your coolant tank had fluid in it and your radiator was low..i'd suspect a bad seal on the cap..what i mean by a bad seal..is when your engine gets hot it will push fluid into the resivour and as your engine cools it will require that fluid back but because it cannot create the vacumm it needs to draw the fluid back into the radiator it stays in the resivour leaving your radiator half full. i had that problem on a long trip. what i done to cure it was bend the tabs on the cap to create a tighter seal..been working fine ever since.

+1.  Had the same thing.

MP

[custom1]

i would keep an eye on that radiator..if your coolant tank had fluid in it and your radiator was low..i'd suspect a bad seal on the cap..what i mean by a bad seal..is when your engine gets hot it will push fluid into the resivour and as your engine cools it will require that fluid back but because it cannot create the vacumm it needs to draw the fluid back into the radiator it stays in the resivour leaving your radiator half full. i had that problem on a long trip. what i done to cure it was bend the tabs on the cap to create a tighter seal..been working fine ever since.

+1.  Had the same thing.

MP

Could also be a bad hose between the rad and overflow bottle. Pushes the coolant out and some makes it to the bottle and some leaks out and then sucks air back as it cools.

[MP]

i would keep an eye on that radiator..if your coolant tank had fluid in it and your radiator was low..i'd suspect a bad seal on the cap..what i mean by a bad seal..is when your engine gets hot it will push fluid into the resivour and as your engine cools it will require that fluid back but because it cannot create the vacumm it needs to draw the fluid back into the radiator it stays in the resivour leaving your radiator half full. i had that problem on a long trip. what i done to cure it was bend the tabs on the cap to create a tighter seal..been working fine ever since.

+1.  Had the same thing.

MP

Well, bending the ears down a little on the cap, so it fit tighter, fixed the problem.  It that does not, then put a new hose on. I like doing the cheap and easy things first.

MP

Could also be a bad hose between the rad and overflow bottle. Pushes the coolant out and some makes it to the bottle and some leaks out and then sucks air back as it cools.