[SouthernCowboy]

2000 Yamaha Big Bear 400 4x4 oil cooling fan problem

I have a 2000 Yamaha Big Bear 400 4x4. I bought it new in 2000 and sold it in 2002. I bought it back a week ago. I've not heard the oil cooling fan kick on since I got it back. I rode it for two hours one day and never heard the fan come on. It seems like I can remember it cycling on and off when I had it before. I ran a hot wire to the fan and it came on. I unplugged the connector off the sensor and put a wire in the connector. The oil light and fan came on. Does anybody know why my fan is not cycling on and off like it should?

 

[SouthernCowboy]

I rode it yesterday for 7 hours and still the fan didn't come on. Does anyone know how these fans work? I'm waiting on a repair manual. I was told the oil cooling fan not running wouldn't damage my engine. I still worry about it though. I like for everything to work. Any information would be appreciated. It's driving me nuts.

 

[SouthernCowboy]

I took a 19 mm wrench and took the thermo sensor out. I took a multitester and checked to see if the sensor was opening and closing the circuit. The circuit open and closed fine. I plugged the sensor back, but left it out of the block. I turned the switch on and heated the sensor. The fan kicked on! When it cooled, the fan turned off. I tried it again with the same results. Could it be that its just not getting hot enough? I rode it for 7 hours in 47 degree weather. I still swear it came on in the snow a lot before.

 

[Code]

Cooling fan

I have done the same thing both of you have done. I put a toggle switch in up by the handlebars so I can run the fan when I want to. I read where the temp has to get 225deg for it to turn on. I think with the air cooled motor they just don't reach the temp. Hope this help.

 

[SouthernCowboy]

Thanks for your reply Code. I thought about the toggle switch, but if it doesn't get hot enuff I guess I just won't worry about it. It's been 9 years since I had it, but I seem to remember the fan kicking on and off a lot. Even with snow on the ground. But my memory ain't too good. I just wish I knew if my fan is working like it's supposed too. I don't want to damage my engine. I rode it yesterday for 7 hours and still never heard the fan. I dunno.

 

[SouthernCowboy]

Still no fan. I have rode it two weeks, but I have been riding it a lot easier than I did 10 years ago. It used to be covered it mud too, which might make it run hotter. I think it's just not getting hot enough. I'm just gonna ride it. Let's call this case closed.