Originally Posted by TLC

Do you see any coolant coming from the water pump housing? I should have a weep hole to let you know it its a seal problem.

Not sure if the H.Os had the cam problems?
The 500 Scrambler got the High duration H.O cam in 1998 where as the Sportsman did not get it until 2001, two years later.

Originally Posted by old polaris tech

Yes they had cam issues on the early Scramblers,but don't think that's the problem of over heating. Pull the radiator cap,elevate the front end and let the engine run and fan cycle on and off. Should see coolant moving in the radiator a little plus check for any leaks under the water pump housing or elsewhere. Could be a trapped air issue if the coolant level drops in the radiator. May just need to be topped off after that. Also something simple as needing a new 13 psi radiator cap could be the problem. If the fan doesn't kick on,could be a faulty radiator sensor or the fan circuit breaker under the front panel causing this which can cause one to overheat.This was one of the last models to have the sensor at the top of the radiator and could short out if coolant got too low stopping the fan from operating. Item #15 Dirt Cheap Yamaha, Polaris, Suzuki & Kawasaki OEM Parts & Accessories – Cycle Parts Warehouse And yes if coolant has run low long enough it can melt an impeller from cavitation. Just check the fan operation and for any trapped air or leaking first.

Originally Posted by old polaris tech

If it's bubbling then it still has air. Try squeezing the hoses and lifting the machine a little higher to see if it helps. You can do a pressure test on the cooling system and see if it holds 10 psi. This way you can tell if its in the cooling system sucking air or a small leak somewhere. Also again doesn't happen often but impellers can melt from cavitation and heat or the nut can back off causing flow problems.Plus yes what TLC said on the radiator behind the fan. Another common area that people over look.

Originally Posted by TLC

My friends 700 Sportsman was over heating and over flowing and steaming from the overflow bottle due to baked hard mud in the rad fins.
The bottom of the rad looked ok but the top half which was hard to see was jammed tight with baked mud.

Originally Posted by stendori

basically what they are saying about the rad being blocked would be on the fan side. if you look at the rear side of rad and it has mud packed in the fins then it could be part of the reason off the over heating. also as opt mentioned if there is any air in the system it will cause over heating as well. if you carefully run your hands up and down the hoses from the engine it should be the same hotness to see if the impeller is working or not and to see if the coolant is circulating.

Originally Posted by stendori

basically what they are saying about the rad being blocked would be on the fan side. if you look at the rear side of rad and it has mud packed in the fins then it could be part of the reason off the over heating. also as opt mentioned if there is any air in the system it will cause over heating as well. if you carefully run your hands up and down the hoses from the engine it should be the same hotness to see if the impeller is working or not and to see if the coolant is circulating.