I have a 99 Magnum and I am experiencing two problems that I cannot quite pinpoint. One is that the engine kept overheating. I tested the fan switch and realized that it was faulty and this is probably the cause. However is it normal that the motor overheats in minus 10 degree Celcius temperatures? I didn't think the fan would have to engage at this temperature.

The second problem is that gear oil seems to be forcing its way up through the vent hose on my back gearcase. Not a lot but enough for me to notice it. Should I be alarmed?

Any replies would be appreciated.

Curtis

 

On the overheating--could you have a bad thermostat?

 

Curtis, do you have a 500 Mag or a 325? (if it’s truly a ’99 it would have to be a 500) At the risk of being redundant, if it’s a 500 Mag (water cooled) I’d check the thermostat. Last January, riding in temps of -10 to 25 above (F) a bad thermostat in my SP500 had the hot light turning on at an idle or an above average load. An easy cruise would cool it enough to turn the light off. It never actually “overheated.”

On your gear case, is this machine new? How many miles? If you’re in the break-in period it may just be a little over-full.


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FloodRunner, on the Wisconsin River

 

If your air-cooled, you need the fan. If your
liquid cooled. In these colder temps, My fan does not engage and atv does not overheat.

I dont know the answer about the gear oil.

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Check your radiator. Is it clogged with mud or snow?

 

Wouldn't the snow melt if it was hot enought to over-heat?

 

As these guys said check the fan and the radiator esspecially the radiator to be sure its not clogged up. Also if you use a large key ring (and some others can elaborate on this)believe it or not it can hit the gas cap when turning and knock the switch into a "half off" position where the cooling fan want run and the alternator won't charge, unlikly but I wouldn't rule it out.

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Kevin Gowdy aka Kagey 1999 Polaris Magnum 500

 

In my experience, for some reason, it seems like winter time is when machines will overheat. My brother's '99 Sportsman 500 overheated when he was going through snow and the radiator grill got packed full of snow. It is far enough away from the radiator so the heat won't melt it much. Kagey, so you must have had this experience with a key chain turning your machine off. I had that a couple times when I was riding the Sportsman 500. I never could figure out why it would shut off, this was when I was plowing the driveway, I thought I was accidentally hitting the kill switch, but every time it stopped the ignition key was on "off". The keychains like to hook on the gas cap, and when you turn, they turn your machine off. You wouldn't believe how many people I've seen that were swearing at their machine because it keeps shutting off, then when I tell them it's their keychain, they are relieved and wonder how something not worth a pinch of crap can do that much.

 

One time a saw a picture of snow, it's kind of like white mud I think. But you guys can try what I do in the mud. I have 2 bungee cords holding screen-mesh from a screen-door on a house on the radiator guard. When it gets muddy, I just pull the mesh off, wash it or just dip it in water, and put it back on. So far no more clogged radiators.

 

Curtis,
Have you drained or topped off the antifreeze lately?.. The reason I say this is because you can get too strong of a mixture and actually lower your coolants boiling point. If you are unsure about this, just drain and refill it with a 50/50 mix of antifreeze and purified water. Oh, another thing, either pressure test or replace your radiator cap.. They are kinda expensive from the dealership, but its the same cap that most sub-compact cars use these days.. Just without the Polaris tag ontop. I bought one from Western Auto for under five dollars. (Robert Shawl brand)
Good Luck....