Ok guys this is an update to my other thread (05 sportsman 700 efi) so far we have checked all the fuses the relays the relay connections, the thermastar sensor, the plug going to the sensor, the thermostat, we installed a new filler neck a new 13-psi radiator cap we tested the fan that all checked out good, we pulled all the hoses and drained the system we even checked to see if the water pump was good which seems to be fine, we just cant crack this one what gives any other suggestions??? when we drained the system we purged it for air then did a new refill as the machine was warming up we were filling the radiator as needed as it got hotter the fluid would rise in the filler neck and boil over or go into the overflow we have confirmed circulation from the radiator to the water pump through the engine to the thermostat back to the radiator like the service manual shows However the only 2 things that we could possibly think it might be is either the ecu unit or could it possibly be the upper inlet of the radiator is clogged somewhere and not allowing the fluid to circulate back through the radiator?

 

How many of you have had to replace a radiator due to overheating issues???

This machine only has 90 hrs on it and has never been mudded or used for plowing or anything of that nature

 

you said you replaced stuff,air in the system?

 

We drained the whole system, pulled the hoses, re-filled it and purged the system so I dont think its air? but Im not positive................

 

I have a 05 Polaris Sportsman 500 HO and i had the same problem u have. I tested the thermostat and it worked purged air changed coolant cleaned radiator REALLY good. Then i got a recall notice for the ecu or ecm. Took it in for the ecu or ecm. The recall also fixed my overheating problem Old Polaris Tech might know about this?

~Polaris man with issues

 

The fan is working ?, make sure radiator is really clean, washit thoroughly from the front and rear.

 

Problem is we were told the recall is for carburated models only not the efi's
as for the fan it works
next we are thinking of removing the radiator and cleaning and blowing it out with an air compressor

 

when you put the t stat back in did you make sure the hole in the stat is at the top.We have raised the rear of the machines to help with bleeding the air out of the system.ecm recall was for carb machines only.

 

Just curious but what hole? is there a diagram of this shown like in a service manual or something?

 

there is a small hole in the t stat should be just below the gasket that goes on the edge of the stat.May be in the service manual I will look tomorrow when im at work to see if theres a pic of it. the hole lets air purge out of the head side of the stat with out the stat opening.