my bike keeps overheating.....very clean rad, stat checked and working, coolant level good, fan wasnt coming on so i jumped it to run constant....didn't help.....coolant pump seems to be working (replaced it last year when mech. seal started leaking dont know where else to go with this.......Thanks for any help...............

REPUS Dave

 

1. have you checked the actual water temp. to see if the warning light/sensor is bad?

2. have you had this problem since you replaced the pump? Maybe the pump was bad from the start.

 

Okay, sounds like you are describing two problems and not one. First, if your fan is not coming on, then you have an electrical issue.....99% chance that it is the thermostatic switch located in the radiator, especially since it does run when you supply 12v to it. This issue by itself WOULD cause your quad to overheat. BUT.....you are saying that it STILL is overheating, even when you jump the fan so it runs all the time...... This insinuates a seperate issue. If your radiator is not clogged with mud, and your pump is doing what it is supposed to do, then I am going to guess that your thermostat is stuck. In case you don't know, the thermostat is a little temperature controlled valve that regulates flow of coolant through the engine. When you first start up and the engine is cool, it remains closed. When the engine reaches a certain temperature, it opens, allowing flow of coolant through the engine. When the quad is at rest for a long period, like over the winter, or if your cooling system is dirty, or for a number of other reasons, The thermostat can fail, and stick in the closed position. Just follow the radiator hose from the radiator to the engine. The hose connects to the thermostat housing on the engine. There are two bolts that hold the housing to the engine. Remove the hose, remove the two bolts, and you will find your thermostat. Plop a new one in, refill your cooling system, and I bet your problem is gone. Caution: DO NOT DO THIS JOB UNLESS THE ENGINE IS COMPLETELY COLD! Hope this helps. Keep us posted Oh yeah, Replace that fan control switch too.

 

I had this with my 2000 500 sportsman. I would see bubbles in the overflow and with a Rad cap replacement all was ok.

 

is it boiling over or justthe lights coming on? how long does it take to over heat?

 

If the rad cap is not holding pressure it will boil over before the fan turns on. A new cap is cheap try it.