I have read many of the threads here about overheating, temp sensor, radiator's overfilling the overfill tank, but I haven't seen one that resembles my problem.

After engine running for a while the temp light was coming on. I jumped the fan and sure enough, the fan would run. I changed the Thermal Sensor on the radiator and thought I fixed the problem (light did not come on and fan would when engine came up to temp).
But now a new one appears. It appears I am leaking around the Thermostat housing. I see a little fluid coming out of that housing and most is burning off, but a little is running down onto the skid plate. I had a full coolent overfill tank, but after 30 minutes of riding it is empty. My hoses to and from the engine appear normal temp (one hot, one warm). Light did not come on, fan does. I think I need to clean the radiator a bit more, I would say it is mostly clear (I need to wait until it is above freezing here!).

My questions:
Does this sound like just a leaky gasket? Can I buy just the gasket or the whole thermostat/gasket combo? Are there any products on the market to reseal the thermostat housing without having to buy a new thermostat, as I believe the thermostat is working? Is there a underlying cause of the leak, or just something that needs to be replaced after 11 years? I haven't tackled a thermostat before, but it looks easy enough and you can certainly get to it. Not sure I like the price of a new one. Anybody have a part number of one that will fit a 1999 500 Sportsman. I read that NAPA may be the best solution there.

Thanks Guys!

 

there isn't a gasket on the thermostat, they use a gasket maker silicone on that, and i think theres an o ring in there, " don't quote me on that" just take the thermostat off and see if there is an o ring if not put some silicon on it and slap it back together

 

pull the stat and seal it with VHT silicne

 

Did a little more investigating today. It is defiantly leaking around the thermostat, seems like it is leaking on cold start and during warm up. After a while didn't notice the leak. I think I will pull the thermostat and try sealing it up again. Any other products out there for this?

 

There is a 'O' ring in there that appears bad. Any solutions here? I really didn't want to pay for the whole thermostat + 'O' ring when i only need the 'O' ring. Doesn't appear to be any gasket or other sealent used. Just the 'O' ring. Am I missing something?

 

Any auto parts store will have an o ring. I use both the o ring and a LITTLE BIT of silicone.