Kawasaki Vulcan Forum banner

1 - 9 of 9 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter #1
While on my way home yesterday, I glanced down at the instrument cluster and noticed the Red Light for temperature was on. Signaled to get over to the emergency lane, pulled in the clutch and just let the bike slow down by its self. The light went out so I figured it was due to the outside temp of around 115. Several miles later it did it again and again I pulled in the emergency lane and repeated the process. After I got off the freeway and came to the stop light it again came on and did not clear. Made it home and checked that the radiator was clear, had coolant and the fan would spin by hand. Forgot to check the fan was running before I turned the bike off.

Earlier this year I changed the clutch pack. I do not know yet if I reconnected the fan wiring under the seat.

Before I drain the tank, anyone know of a way to check the if the fan relay is working or to be able to activate it and check the fan works?
 

·
Registered
Joined
·
3 Posts
Discussion Starter #3
Did that and the fan kicked right on. I let it idle and after a while the fan came on then too. Also checked the oil level, its full.

So right now I am going to assume that it was because of the air temperature.
 

·
Premium Member
Joined
·
1,482 Posts
If you are moving, 115° should not cause it to overheat (edit - if everything is working properly). If you are in stop and go traffic on a day that hot, yeah, it might overheat, but not when you are moving.

You know your fan is working from what you have done. Likely culprits at this point are a bad radiator cap (not allowing enough pressure to build up), a bad water temp sensor, or a bad thermostat. It is probably not the thermostat since the light went off, at least for a while, when you got moving and got air flowing thru the radiator, though after a while, even that was not enough.

If the cap has a few years on it, just replace it. That's one of the few things that you should just throw a new part at just to see if it fixes the problem. You should replace the cap every few years, anyway.

(Edit: If a new cap does not solve the problem, I suspect the water temp sensor based on what you have said. At a lower temperature, say 100° or less, just moving would probably be enough to get or keep the coolant temp low enough to make the light go out. At 115°, moving might not be enough if the sensor is not working causing the fan is staying off.)

There are tests in the service manual for checking the water temp sensor and the thermostat. If you don't have one, I suggest you obtain a copy. Maybe someone will chime in with a link to the service manual for your bike.

Other possibilities: old coolant hoses that are too soft and not allowing sufficient pressure to build up. A blockage somewhere in the cooling system. I would eliminate the cap, sensor, and thermostat first, though in that order. I recommend changing the cap, hoses, and o-rings every few years as preventative maintenance.

I change the coolant every two years, flush every 4 years with an alkaline auto flush (never vinegar!), and change the hoses/o-rings every 4 years. One two year interval, I flush and change the coolant. The next one I change the hose/o-rings and the coolant. Old coolant can lose some of it's ability to transfer heat (as well as cause corrosive damage to the system) and minor clogs can sometimes be eliminated by changing the coolant and by flushing the system.
 
  • Like
Reactions: Tourer and Lesblank

·
Registered
Joined
·
1,518 Posts
Where are the O rings you're referring to? The parts blowup doesn't list any. It does show what may be O rings, but just calls them replacement parts.
 

·
Premium Member
Joined
·
1,482 Posts
There are metal pipes that connect parts of the cooling system. They are sealed with o-rings. These actually seem to cause more leak problems than old hoses do. Lots of folks find trickles of coolant that can be traced back to those o-rings leaking.
 
  • Like
Reactions: Tourer

·
Registered
Joined
·
367 Posts
I had an overheating problem on my 900. It turned out there was an air pocket left in the cooling system after I changed the fluid. The overflow bottle had plenty in it but for some reason the system wasn't "sucking" it back into the system. Removing the cap revealed the coolant shortage and it took about a pint to fill it to the top. Never had a problem since.
 
1 - 9 of 9 Posts
Top