yes hello to all as per subject line what would cause my atv to overheat, and cause the fan not to kick on. u see i recently repaired/rebuilt my engine. and after i put it all back together it ran great for like a month and here lately i noticed it has been overheating, and i cant figure out why so maybe OPT can help me or any one else have any ideas. I have checked to make sure she has got anti-freeze in both the main fill port and reservoir.
THANKS IN ADVANCE
RUBEN

 

Check that the fan motor works. Just jump fan motor wires to a battery. Most common cause was the fan sensor at the top of the radiator shorting out when coolant got too low. Item#6. 1995 Polaris SCRAMBLER 4X4 (W957840) Cooling System Scrambler | Cycle Parts Warehouse Plus did you bleed the screw on top of the head? If not that's another cause for the 400s to over heat because of trapped air pockets.Plus you have to have a good battery and charging system for the fan to work properly.

 

yes i did bleed the screw that you are talking about , and i am pretty sure that the charging system and battery are all pretty darn good , i will check out that sensor your are talking about tomorrow. but i know for a fact it is overheating because i have got a trail tech tachometer on it with one of those speedometer and temp. monitoring system on it. It is almost like the coolant isnt circulating although it was right after i rebuilt the motor. this started like a month or 2 after i rebuilt the engine. i checked both the coolant and the engine balancer fluids to make sure one wasnt in with the other, which they werent. like i said it is like the coolant isnt circulating,
THANKS IN ADVANCE
RUBEN

 

Pull the return hose to the radiator when its a little warm,put it in a clean pan and crank the engine up. If the water pump is doing its job coolant will flow into the pan.If that's working ok then could be the radiator itself is clogged/dirty or the radiator sensor or fan motor that you mentioned earlier.

 

okay thanks OPT, if it isnt flowing what could it be, and also if it is flowing how would go about checking to see if the rad. is plugged up.
THANKS AGAIN OPT
RUBEN

 

Again step by step.. Check that the fan is working.If not,that could be the problem. If it is working,then usually the sensor wont allow the fan to kick on.Another is the back of the radiator.People over look it and it can get caked with dirt and mud. Your first post you say the fan isn't working,that in itself is a problem right there as this engine will over heat quickly without it.

 

okay thanks opt so i did check to see if i had flow and no i did not have flow. what could it be.
THANKS
RUBEN

 

Straight shot from the water pump to the engine and out,no thermostat.If coolant isn't moving then the impeller nut may have loosened up.

 

yeah the coolant isnt moving i too was thinking that the impeller nut had come loose. oh shucks here is to tearing her apart all over again.
THANKS OPT
RUBEN