OPT, the overheating resurfaced over the weekend. The radiator is still very clean from my last cleanup and the fan is still kicking on. We even took off the front cover to see if we can get more air to the radiator. (Dodging evey stick in the woods...lol).

At first, we took quite a few breaks to wath the SXS hill climb. But once we hit the trail......10-15 minutes, it started flashing HOT again. I and a few others stopped. We could hear the fluid coming out the overflow tube for a brief moment. I checked the overflow bottle once it cooled and we were at the minimum. Once we started again.................3 minutes at the most..........flasing HOT but not spewing each time. My stops between cool downs are anywhere from 20-30 minutes each time and most of the time, I leave the fan running to help in the cool down.

Whats next?

 

Jack up the atv with the front tires off the ground about a foot,(manual says jack up the rear tires,but seems like the front worked the best for me) run it without the cap OFF until the fan cycles on and off several times,then top off the coolant,and replace the cap.Then ride it around. You still may have trapped air pockets in the system. If it continues to get hot,then if you have access to a radiator pressure tester,cooling system must hold 10psi for at least 10 minutes with no drop! If this shows ok then could be the temp sensor itself on the cylinder needs to be checked/replaced(especially if the hot light comes on before the fan does) plus could be as simple as a bad radiator cap. 13 psi caps are available at any auto store for about 6 bucks. As long as you've ruled out the fan motor itself and radiator is clean. OPT

 

Thank you OPT!! I will let you know as soon as the weather breaks and I can get her all cleaned up for more maintenance.

 

As you can see, the last time that I posted on this overheating was on 12/17. OPT, your trick worked. I have been riding for close to three months (aprox 10 rides) and no trouble......................................until now.

yep, after about 22 miles with plenty of breaks in betwwen, the overheating came back.
1) the fluid level is good
2) the radiator is not full of mud on the outside (still pretty clean) but even cleaner after the help of a small waterfall
3) the screen protecting the radiator was gummed up a bit but that was easily cleaned with the help of a small waterfall
4) no obstructions in the fan (fan was running)

Could this be inside the radiator? or even possibly in a thermostat? What is a good procedure for flushing the radiator. This is starting to get a little old.......some one please help!!!!

 

Thermostats are rarely the problem,but you can take it out and drop it in boiling water. You can see if it opens or not.You can flush the radiator by opening the drain at the lower right of the radiator and just using a garden hose if you want to flush the system while it's running. After this just install coolant(leave the drain open while running) until nothing but coolant comes out,then shut the valve. You still have to leave the cap off to purge any air while the front wheels are off the ground. You can just remove the radiator if you want and have it checked for any clogging or pin hole leaks at any radiator shop. Any small leak or clog can cause overheating problems also. Remove the sensor on the side of the cylinder while cool. Check the resistance. Should be between 2.0 to 2.5k ohms resistance cold. At 212 degrees(boiling ) should be 0.186 k ohms (approximately). Also you can remove the fan connector at the sensor,the fan should run with the key on. You can lightly stick the ohm meter test probes on the Orange/Black and Brown wires of the fan and test amperage draw. Should be less than 15 amps.(weak or slow fan if more than that) Another thing I can think of is the 20 amp circuit breaker that might be weak that sends power to the fan relay,then to the fan motor itself( has two black relays by the fuse block) Left relay is main power,right is the fan relay. These two relays are the same and can be swapped around also. The circuit breaker has caused problems for us at the shop in the past. It's located on the harness in a pouch up from the fuse block. Last thing if you have access to a coolant pressure tester. The pressure must hold 10psi with NO leak down. A LOT of things to check,but it's a process of elimination on a recurring problem. OPT

 

Thank you OPT. I took the entire front apart. Because it wasnt a big job, I actually drained and took the radiator out of the 4-wheeler. I just took normal water pressure and flushed it through all the fins until no more mud was coming out. I couldnt believe how much mud was on the backside. Just for precaution. I ran water through the inside also. Since I already had it apart, I done the same to the cooling fan and lubricated with some Teflon spray.

_________________

 

Glad you finally found the problem. I've had to remove plenty of em to get all the mud out especially at the back of radiators around the fan area.You might think it's clean until you actually remove it and are able to clean it properly.

 

I seem to have any problem that comes with overheating. OPT has been a great help and has had me up and running in no time through it all.

I go through it all to keep my radiator clean inside and out. That is no longer an issue. Just recently, I had to replace my cooling fan. That helped for a month. Now, I overheated yet again............
1) radiator clean both sides and inside and out
2) new fan is awesome

On a nice long ride, we were at cruising speeds. We didn't ride hard all day. Well, except, I had to show a King Quad how the Sportsman can handle a certain hill climb. Yep, I overheated again. I went through the normal checks. I had no fluid in the overflow bottle and the fluid in the radiator was low. We topped both of them off and continued on our way. I didn't overheat on the way back but the fan seem to run continuously with very little breaks.

I got her home, cleaned her up and started checking fluids. My radiator bottle is empty and the radiator is low again. Being curious, I start tracing everything that's associated with the radiator. I found the leak! Except I didn't like where the leak was coming from. It was coming FROM OR NEAR a weep hole in the water pump area. At the same time, I hear a new rattling sound that I have heard lately is also coming from the same area. (Honestly, I thought my heat shield was rattling). Now, Im worried so I climb onto Polaris web page looking for a water pump and a parts break down. Low and behold, there is more to it. The water pump (impellar) is attached to the oil pump shaft.
How does this area work for cooling? I popped off the water pump cover. Guess what? The impellar looks in great shape. I see a passage that goes behind the impellar housing that goes to maybe the oil pump area? I removed the impellar and see a seal that looks like its in good shape. The shaft has no play in it. I haven't removed anything else yet. Beyond this I get into the oil pump area and I don't want to ruin this other seal if I don't have to.
Any ideas? If it is coming from the weep hole, what may have caused that? I don't want to take it apart if it was just coming from one of the two gaskets? But the rattling sound has me worried that it might be a bearing but there is no slop in the shaft.

 

Weep hole on the the bottom of the cover is there for a reason. If coolant leaks from it,the w/p seal has failed,if oily residue is evident the inner oil seal is leaking.This is also called the "dead mans" space as between the w/p and oil seal it should be dry,hence the weep hole. Best way I can tell you to replace this is by the manual! I've had guys try to pry out seals in the 500 engines and damage shafts. Same thing on the 700 and 800 engines. The oil pump shaft also serves as the mounting for the seals and w/p impeller. Manual states to pull the flywheel and remove the stator out of the way. Then you have full access to remove the outer cover and on the work bench pry out the old oil seal(easier to do it now than if it leaks later) then just knock the w/p seal out,replace the new oil seal,w/p seal and reinstall the cover. Then one final time of bleeding the air out of the system and you should finally be okay. Dirt Cheap Yamaha, Honda, Arctic Cat & Polaris OEM Parts & Accessories – Cycle Parts Warehouse
Here's a free 2009 800 pdf service manual,same as yours on w/p replacement and goes into detail.NOT that hard a job if done right!Just click on the link for the 800. http://www.partshark.com/custompage3.asp?pg=polaris

 

I did not see an oily residue. This was all anti-freeze. If there wasn't any oily residue, would I need to replace seal #11 (on parts break down)? Which seal would cause oil to come in?