Ok I checked the fan last week.. fan is good but the thermocouple at the bottom of the radiator isnt. I took the sensor out of the equation and installed a rocker switch on the headlight pod to turn the fan on and off. I drained radiatior and flushed it out about 4 good times and filled it with coolant and purged the air in the system. So I start driving it around and after about 5 minutes it starts spewing out of the overflow.. so I shut it down. Next day I pull the thermostat and check it and it looks ok.. I guess... not really much to it except for a spring and a collar on the outside.. there was coolant behind it so im not sure what to think at this point.. im starting to think that cutting out the sensor at the bottom of the radiatior by installing the rocker switch might be throwing the computer off.. but i dunno.. any ideas??

 

Sensor(4010161) is around $45 dollars at Cycle Parts Warehouse,may be cheaper elsewhere. Trying to just bypass this system cause more headaches than it's worth. Just replace the sensor,jack up the front end of the atv with the tires up about 8-10 inches off the ground,fill the radiator and add coolant slowly as the level in the radiator goes down as the engine warms up,plus you should be able to see coolant slowly flowing back into the radiator as the engine warms(this means the water pump is ok). Leave the radiator cap off and let the fan cycle on and off several times to purge the air.May take a while to do this! Plus if in doubt about the 13 psi radiator cap,most auto stores have em for about 6 to 8 bucks.Hopefully this should solve your problem. This model is hard to purge the air out because the return line runs back into the filler neck instead of the radiator directly. They didn't change the cooling hose routing until the 2005 or 2006 models. The only other thing I can think of if I haven't already mentioned it is to check the sealed pouch(10 amp fan circuit breaker) to make sure it has 12 volts on each side of the breaker wires going into the pouch to eliminate it as a problem. OPT

 

Bypassing the sensor was no headache at all OPT.. the headache was the impellar in the water pump housing.. there was no need to replace the sensor.. I am an electrician I just never worked on an ATV. Either way.. Got a new impellar and "burped" the cooling system and bike runs like a charm. Im really not sure that the advice given people like .. "buy this" or.. "part number that" is the best way to go. Getting people to spend money on things that they dont need to spend on is not good. I hope anyone that has had my problem and has seen this post doesnt go out and spend money on all these new parts. check the water pump impellar..

 

Did you read the middle of my previous post about coolant flow through the radiator as a check for the water pump?Air in cooling the system can cause cavitation which can eat up plastic impellers from heat. Same as it can do on an impeller on a water craft if it sucks air through the pump housing. I list all possible things that could happen from my years of experience and don't twist people's arm to purchase parts, I just give them avenues to explore as to what might be wrong. Most of the people I try to help are the ones who can't afford $100 an hour shop labor charges. In turn though if most of the people just had a manual,either a hard copy or a pdf download, they wouldn't have to go through a lot of the problems they're having and only have to post when they're absolutely stumped. This I do try to twist people's arms about. OPT

 

Old Polaris tech: Thanks for your input but I can no longer find that part listing 2460944 from the cycle parts wearhouse. Do you have any other suggestions ? and thank you in advance

Gary

 

10 years is a general rule of thumb on parts that dealers and a lot of online suppliers can keep in stock for certain machines. Some items you can find everywhere,but items like your main harness 2460944 that was only used on a small run of atvs would be one of the first things to hit NLA status. You can check a Polaris dealer and see if they can help,but if they can't you're down to salvage yards,etc. Just a few machines used this part # and only in 2002.

Usage : 2460944

Year Product Model Assembly
2002 ATV SPORTSMAN 400 ELECTRICAL/TAILLIGHT - A02CH42AA
2002 ATV SPORTSMAN 400 ELECTRICAL/TAILLIGHT - A02CH42AA
2002 ATV SPORTSMAN 400 ELECTRICAL/TAILLIGHT - A02CH42AA
2002 ATV SPORTSMAN 500 ALL OPTIONS ELECTRICAL/TAILLIGHT - A02CH50 ALL OPTIONS