I have a 2004 Grizzly that seems to be overheating. The temp light will come on, but it does not boil over or show any other signs of overheating. It will happen after a couple hours of riding or after a few minutes of going near full speed for a few miles. I know the Grizzly is somewhat infamous for overheating and I do live and ride around Phoenix, but were talking very gentle rides with the family. Is it possible I have a faulty temperature sending unit or a stuck thermostat? Any info from the group will help thanks.

 

The 04 shouldn't be overheating. Make sure your radiator isn't covered with stuff. I went through some tall grass and my radiator was completely covered with grass seed. Check your radiator fluid level. You may want to drain the system and put Engine Ice in it. Also, make sure you change your oil and filter when you're supposed to. If you do those things and it's still overheating, I would take it in.

 

My temp light has never come on once, Even when it was 90 outside.

 

I don't ride through mud or brush (it's hard to come by out here in the desert LOL), the radiator and the rest of the quad is very clean. This quad has 70 hours on it, the oil has been changed 4 times and the oil filter twice. The overflow bottle shows the correct amount of coolant, but I have not opened the radiator cap to check there. I guess it's possible the dealer did not completely fill the radiator during initial set up. My sister in law will also be riding the exact trail going the exact speed on here 04 grizzly with no temp light coming on so I know I definitely have a problem somewhere.

 

Make sure that you don't have a faulty thermostat. If it is stuck closed it will cause it to overheat. Make sure that your fan motor will cycle on and off. If you are going slow enough and your fan isn't coming on it will get hot. One last thing is to make sure that you don't have an are lock that will impede the coolant flow.[img]i/expressions/face-icon-small-happy.gif[/img]

 

Do you hear the fan come on, before the temp light comes on? The fan should keep it cool enough, even on a hot day, unless youre doing alot of heavy work. Theres a circuit breaker for the fan circuit, check that first, if the fan wont come on. Its #36 in this view.
alba

 

The fan cycles on and off normally. I ordered a Yamaha service manual today so I can find the temperature sending unit, I think it is faulty. The radiator flows fluid and everything else is normal. Like I said before the light comes but there are no other symptoms of actual overheating. Radiator does not even boil over. If the radiator is not boiling over how can it be too hot? It's got to be a faulty sending unit.

 

The wire on the temp sensor could have a short in it or the plug coulc be coming loose. When I got my heat kit it was accidently unplugged and it took me an hour to figure out what was wrong.

 

Okay a little update if anyone has had this issue before. I purchased the service manual from a Yamaha dealer so I could get the spec and even find the temperature sending units. There are two, one for the fan and one for the over temp light. The over temp light is the one I was interested in and is located on the head right next to the thermostat. When the "Thermo Switch" is below 217F there should be discontinuity (an open circuit switch). Once the switch reaches 230F it will have continuity (closed circuit switch) until it reaches 217 again then return to an open state. When I took my thermo switch out and hooked up the ohm meter for the audible signal I immediately got a tone indicating a closed condition and therefor a bad thermo switch as I had suspected. So the good news is the quad never really was overheating. The bad news is I wonder how much a #1 thermo switch will cost at the local dealer.




It will feel better when it stops hurting.

 

Thanks for the update.