2016 Ranger 900 with Razor rear end, monster axles and 31" tires. Built to run in the mountains elk and mule deer hunting. Any way the last 2 years when out in NM, it has started overheating after some hard use like 4 low for miles climbing hills. I shut it down and let her sit for a bit and cool off and then take off for the rest of the trip. Wasnt mud build up on the fins, i even pulled the thermostat, thinking it may be sticking. Still does it.

Now its starting to do it running around my lease with several bags of corn in the back. Im thinking that the radiator itself may be undersized for the mods i did. Any ideas on what to do will be greatly appreciated.

Another note, its started using some oil as well, not burning it or at least cant see any smoke. And no leaks under it. I think the valve guide seals are leaking by, but im not positive just yet, need to get it home and get the head off and take a look.

not familiar with Polaris ... but some things to check (I have on my RTV) radiator cap, thermostat (sounds like you already checked that? but my RTV will run hot with the thermostat removed), radiator clogged with dirt/mud/dust/weeds, is the fan operating properly (my RTV has 2 fans, one on front of engine, one electric behind radiator). Then more serious issues could be cracked head

Gotta burp it. Park nose high(like 4-6'). Remove radiator cap and run the engine until the trapped air is dislodged from the block. The coolant level drops. Refill and drive to see if that helps. Could take 10-15 minutes.

Burping it finally solved the problem with a friend’s Mule.

Grass seed, brush/grass leaves and pollen can clog up a radiator to where it will do that.

Im definitely going to try this next!

There has been some grass/seed and even some dust stuck in places. I cleaned it off best i could, the last time i was in it. Ill try cleaning it better with a water hose.

Could it be that my radiator is not large enough, with all the mods and such it has to be putting an additional strain on engine? I started looking for an aftermarket radiator that is larger for the additional capacity.

Cleaning from the front only pushes the seed and pollen farther into the radiator....need to clean it from the backside of the radiator.

Chunky, read up on purging air from the cooling system. I don't know if this is the original issue, but it might be the cause of overheating now.

This - I buy one of those small window screens from Home Depot and strap it front of the radiator - catches all the seeds, etc. A lifesaver for sure

Here is what I use - works like a charm for me

That looks nice, real nice.

LOL I don't care what it looks like as long as it works!

I channel Cousin Eddie often. He's a philosopher of sort's.

yeah I can see that

And flushing it out often takes getting the spray nozzle at the precise angle to ensure everything that's caught deep inside the fins will flush out. I thought I had a tractor radiator cleaned out once until an old timer told me to try again and make sure the water was being forced straight thru the fins. And dried mud may need to soak a while before it will flush out.

If you use water to wash out radiator fins, follow it up with a blow out with an air compressor. That will keep the wet dust from drying and becoming caked dirt.

Im not sure on the 900, but i have a 2014 Sportsman 800. I had to replace the temperature sensor because the fan was not cycling as often as it should. Is your fan running when the high temp light comes on?

If you haven't figured it out yet and still having issues with your Ranger Check out Polaris Ranger Club Forum (PRCForum) those guys know their stuff.