02 RMK800 water problem

[Glaciershaker]

Hey just picked this sled up at took it out for a spin today. It's over heating because it's not circulating down the long tunnel to radiator and back down other side into the radiator at bulkhead. Pump is pumping. T stat is working. It is flowing through t stat to the first "T" at that T it's flowing down to the bulkhead radiator and back up to the fill bottle. It isn't flowing though the brake cooling. But it's not plugged. I can open and blow air into it and it goes through. Is there a chance the pump can't pump that distance if it's weak? That pump either pumps or not and it's flowing water. Any ideas?


Thanks,

GS

 

[BB454]

cooling

If it overheats immediately then pull the pull starter and make sure the belt is OK. I have had a couple that the WP impeller has come off. You can confirm that through the hose fitting but you will need to drain the antifreeze down. If you haven't already, pull the thermostat and drop it into hot water. I have seen them jam after overheating.
If the system was open recently then it may be as simple as a bubble in the rear cooler.
The pump is mechanical and if the impeller and belt are intact then it should circulate. Just because that hose is a little warm doen't mean it's pumping. It will get warm just by convection close to the motor.
Only 5 things that can stop it. Belt, impeller, thermostat, a bubble, or bad radiator cap.

 

[ericlowe4696]

just had the same problem with mine i took everything apart and everything was fine. So when i refilled it i put the front of the sled on my cherry picker and jacked the sled up and then filled it. I have had no problems with it since then

 

[Glaciershaker]

I worked the air out of the system with nose high and low. The system just wasn't circulating through the entire system. It seemed to take the path of least resistance and just went to the center cooler instead of through brake and down around running boards and rear cooler. I'm going to dig into the pump and look at impellor. Then I'm going to take that "T" that is before the brake and run straight to the brake and not to the center cooler. I just don't see why to run hot water into that cooler. There isn't much cooling surfaces on the machine and I think it needs all the help it can get to cool. Also what is the by-pass for below the "T" stat back to the pump? Again I'm not sure about this one. Anyone???? Oh I put the t stat in the coffee machine at work and it was opening and closing.

 

[customfarmer]

I would lean towards the idea of an air bubble in the system. I had a similar issue with my 910. It would overheat at times without any real rhyme or reason for it. I bled the system numerous times to no avail. Finally, one afternoon it started spewing coolant in the middle of pretty gnarly climb, I wound up stuck with the skis pointing almost straight up, and figured it was a good time to try and bleed the system again. As soon as I popped the cap it literally belched a BUNCH of air. The point to my rambling is to get the front end way higher than the rear when you bleed.

 

[Glaciershaker]

I had it almost straight up. That's how I bleed all systems up and jump it aournd and back up. Spent at least an hour at it. The guy I bought it from replaced the coolant bottle. Now any chance it's directional? I just saw a picture of a motor with it 180 from mine. I just think it's a bottle with same open ends but I didn't take it off.

 

[BB454]

Bottle is not directional. The bypass hose that goes from the head around to the waterpump lets the motor warm up before the T stat opens. This aids in preventing cold seize. You can crack one of the hoses back on the rear cooler to burp any air out. Just loosen the clamp and slip a screwdriver under the hose to vent the system. Later edge models have a bleed screw on some of them.

 

[Glaciershaker]

It's not air in the system causing this. It's not circulating. I'm pulling motor and checking out water pump and the run on the crank and bearings. Do you know why there is return back to the center cooler after the t stat opens. At the "T" before the brake? I don't know why you want to add warm water when the surfaces on these have such little cooling.

GS

 

[BILTIT]

Your cooling system is very similar to mine. That is the bypass loop and i have not found any reason why it is there. Everyone says to bypass it and the motor runs cooler so i did just that. I replaced the T with a coupler and plugged the bypass hose coming out of the front cooler. There was also an updated T-stat which blocks the motor bypass completley once its up to temp.

I don't know what my temps where before but now my 800 will not go over 125 in the snow. On hardpack without scratchers it will get up to 145ish.

 

[BB454]

That T is to prevent a large swing in coolant temp when the t stat opens. You can bypass it it you want, just make sure you warm it up good before riding. On my XCR motor in a Gen II, I eliminated the t stat similar to what you are thinking.

You don't have to pull the motor to get into the impeller. You can get to the bolts under the Y pipe. Take the F shaped pipe off the cyclinders by removeing the 2 Allen head screws and loosening the hose clamp on that short hose. Then just rmove the 6 10mm bolts and pop off the WP housing. Impeller is under it and held in place with a nylok nut.

Check runout just by pulling the clutch.

 

[Glaciershaker]

I'm hearing a pretty good knock down there. I think it's a crank bearing. I'd like to spilt the case and look at it.

 

[whoisthatguy]

The two most likely causes of poor circulation is the air bubble in the top of the cylinder head, and the keeper nut loosening just a little bit that allows the impellar to impact the bottom of the housing, and freeze in place. Take your red cylinder head cap off and grind an air vent channel in the fins that trap the air. Also look for coolant coming out of the drain hole below the water pump housing. If you have coolant dripping, then you need to rebuild the water pump. The bearings can also get old and freeze up. How many miles on the sled?

 

[Glaciershaker]

1,200. I'm hoping the knock is in water pump. I'll dig in it. I dont mind to tinker with my sleds. I like to know every inch of it before I hit trail. What is secret to putting that airbox back in? Getting hung up on mag carb and I can't see bottom of boot to see if it's on. Trick? Steering post certain way? Never really had hard time with all my other sleds. This chassis is new to me. Kids bday gift

Keep them coming. I been gone long time flying the other toy

Thanks

GS

 

[whoisthatguy]

Don't tighten up the carb clamps before you slide the airbox in. Manipulate the carb to get the far side into the boot around the carb first, and then push on the carb to get the remaining near side into the boot. A screw driver tip can also be inserted into the rubber boot that is lapped over the carb end, and then worked around the boot to seat the entire boot.

 

[BB454]

I run a screw through the boot flange into the air box at the bottom. This will keep the boot on the box. All of the edge boxes I run have the shelf out and a SLP kit on them. That allows you to reach down in the air box and get it over the carb right. Also bend the back of the bracket that the air box sits on back a little. That will allow it to go down and then forward.