I have a 2001 500 H0 that is overheating. The radiator has been cleaned new thermostat,head gasket and I did check the water pump and is is fine. The fan runs just fine but after you drive it a couple of miles it will start to spray antifreeze out of the over flow bottle. I had both the front and the rear of it lifted up to try and bleed out any air that could be in the system. I am out of ideas and would really appreciate any help. thanks
sportsman 500 overheatig????
- Thread starter chuckb
- Start date
B
big_wally81
Active member
just a thought, i have seen one that the fan was spinning backwards on and it would overheat really quick. otherwise clean the radiator with foaming coil cleaner like the stuff the use to clean the condensor for an air conditioner. just a couple ideas.
radiator cap if the bootle is filling up or overflowing if it's not overheating. pretty common problem. Also check the coolant temp. sensor for fan on the radiator. The wiring corrodes in the sheething coming out of the sensor. The fan won't always kick in like it should.
I have put on a new cap and the fan is working fine. It will sit and run with the fan on and never fill the bottle until I get on it and hold it wide open for about 2 miles, then it will start to fill the bottle. Thanks for the help.
gettin air into coolant, cracked head,bad gasket??
T
theultrarider
Well-known member
That is a pretty common problem here where we ride. Take your radiator out of the wheeler and make sure it is REALLY clean. What I mean is this, when you clean the radiator in the wheeeler you tend to get the faces of it clean, but all the cores are all still plugged up solid with no air getting through it. Very hard to tell if it is truly clean without removing it from the wheeeler. Last one I had like this, I soaked in the bath tub for 3 days and still would not clean out with a pressure washer. Had to start with running a fine piece of wire through all the fins to start breaking up the mud packed in there. Radiator "looked" clean but, you could not see light anywhere through the fins. Weighed about 20lbs less once cleaned right. No more overheating problems after that. Give that a shot even though you think it is clean.
Ive had this happen on a few sportsmans, It is most likely the remote filler neck,That plastic piece where you put the cap on, It sags where the cap should seal, Its hard to see but if you can get a pressure tester you may find it wont seal. When it builds a little pressure it blows by and out the overflow tank.Good luck.
Thanks for all the good ideas i will try the filler neck. I did remove the radiator and had it cleaned and you can see trough it fine.
just put on a new filler neck and it is still doing the same thing. I am out of ideas.
So when the coolant spews out and you stop is the fan running? I know you said the fan was working fine, just trying to come up with some ideas. did it do it before head gasket swap? Is the overheat light on? do you have that little capplug in the overflow cap?
I dont have the inside cap in the overflow jug. It did this before I put the head gasket in. As far as the fan goes it is turning on and off fine and it is running when it boils over.
One other thing. the hot light does not come on until it comes out the jug for a few minutes,then the light will come on, but the fan will cool it down enough to turn the light off at a idle.
H
HSR
Member
Try www.atvconnection.com on the polaris forum.Some good peeps there.
Steve
Steve
you could always wire in a fan bypass switch, Flick the switch on when ever you need to cool it down. I am sure it does not overheat when the fan is on right?
G
Gimpster
Guest
Couple thoughts.
Pressure up the engine with a spark plug adapter to air, top off the coolant and check for bubbles
Double check the cam timing and valve clearance
Also remove the coolant fan sensor and suspend it water with an ohm meter connected to it. Put a thermostat (mercury type) in th ewater and heat it on a stove or portable burner camp stove type deal. See what temp the semsor gets continuity. It may be kicking on at too high of temp leaving the fan system no way to cool down the coolant fast enough to overcome the rising coolant temp
Could also be a bad bearing behind the mechanical seal in the water pump. It is a small bearing in the crankcase. Crankcase pressure may be leaking into the water pump coolant housing when the engine is accelerated causing the oil pump drive gear to 'walk' a little from the bad bearing letting crankcase air into the coolant system past the seals. Since the shaft drives the water pump and the oil pump, the oil pump rotor is cross pinned through the shaft on it's end so it will drive with a little movement from a bad bearing. If the shaft walks a little (climbs the driven gear) on the water pump end of the shaft from the bad bearing, this could be the result, getting air into the system and making the unit hot. I have seen this in rare cases and it does happen, not only on this engine platform but in other manufacturers engines also. You would be suprised at how cheep these inner bearings are. common bearing number is a #6202 or a #6002 on those shafts (I think), anyway, it is a light bearing that can go bad easy
I would pressure check the top end first though to make sure of a head gasket not being bad, or if someone used a scotchbrite pad on a drill to clean the mating surfaces of the cylinder and head. This form of cleaning can leave divits in the mating surfaces or un-eveness in the aluminum so they will not seal. I never use these pads to clean aluminum surfaces, rather use a razor blade instead, by hand to not damage the mating surfaces.
Good luck finding the cure
Post if you do
----- Gimpster -----
Pressure up the engine with a spark plug adapter to air, top off the coolant and check for bubbles
Double check the cam timing and valve clearance
Also remove the coolant fan sensor and suspend it water with an ohm meter connected to it. Put a thermostat (mercury type) in th ewater and heat it on a stove or portable burner camp stove type deal. See what temp the semsor gets continuity. It may be kicking on at too high of temp leaving the fan system no way to cool down the coolant fast enough to overcome the rising coolant temp
Could also be a bad bearing behind the mechanical seal in the water pump. It is a small bearing in the crankcase. Crankcase pressure may be leaking into the water pump coolant housing when the engine is accelerated causing the oil pump drive gear to 'walk' a little from the bad bearing letting crankcase air into the coolant system past the seals. Since the shaft drives the water pump and the oil pump, the oil pump rotor is cross pinned through the shaft on it's end so it will drive with a little movement from a bad bearing. If the shaft walks a little (climbs the driven gear) on the water pump end of the shaft from the bad bearing, this could be the result, getting air into the system and making the unit hot. I have seen this in rare cases and it does happen, not only on this engine platform but in other manufacturers engines also. You would be suprised at how cheep these inner bearings are. common bearing number is a #6202 or a #6002 on those shafts (I think), anyway, it is a light bearing that can go bad easy
I would pressure check the top end first though to make sure of a head gasket not being bad, or if someone used a scotchbrite pad on a drill to clean the mating surfaces of the cylinder and head. This form of cleaning can leave divits in the mating surfaces or un-eveness in the aluminum so they will not seal. I never use these pads to clean aluminum surfaces, rather use a razor blade instead, by hand to not damage the mating surfaces.
Good luck finding the cure
Post if you do
----- Gimpster -----
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I never did find out why it was overheating but the guy that owns it is going to trade it off. Sorry it took so long to reply but I was still trying to figure out what was wrong with it. Thanks again for all the help.