The mysterious disappearing coolant routine on a '02 800 RMK?

Check your o-rings on your heads. If one of the inner ones went out you could be losing coolant into your cylinder and out your pipe without noticing.

They are designed to overflow when overheating. Just like a car. Is it overheating on the snow? Where are you running it? You may need to do a full system purge to see if you have a block somewhere. But if it is merely a slow leak, I agree with the o-ring on the head. I have seen many of those fail...

bad o-ring in the heads, allows compression into the cooling system and blows coolant out the over flow

For sure check the o-rings since its already been hot. You will want to look at both inner o-rings for melting or being squared off.

But its very common for the water pump impeller to strip on the shaft and move coolant too slow or not at all. Also check that the water pump belt isnt broken or stuck thermostat.

Coolant

I have had a couple of water pump impellers come loose too.

A quick way to test for circulation is to feel if both running boards are warm. If only one gets warm then its for sure a flow problem.

Summitstef said:

Just about got this project wrapped up. However, I'm noticing that it likes to drink coolant :face-icon-small-sad. Its a '02 vertical edge 800 with no engine mods. Mixed up and filled about a gallon of coolant/water @-35 into it and burped. No leaks, but it seems as though the level drops sporadically. Any hints or suggestions? :face-icon-small-con

Click to expand...

Don't know if this is the problem with your sled, but.........................here's what happened to my 2002 EDGE-X 800 (6400+ miles)

The radiator cap intermittently contacts the bottom side of the hood and as you're bumpin' down the trail, it causes the overflow bottle to move up & down a little and allows a little trickle of antifreeze to discharge out of the overflow hose here and there,

Diagnosed by placing a wad of paper into the overflow hose, and driving it, came back green.

Then I re-mounted the coolant overflow bottle a little lower to solve it.

Hope this helps

Possible Causes of Boiling Over and Loss of Coolant

Possible Cause #1
The installed O-rings are not the special Polaris High Temp O-Rings. There are standard temp O-rings floating around out there and when a dealer wants to sabotage your sled, he may sell you the standard temp rings, like they did to me. The standard temp rings allow the coolant to get into the cylinder and destroy the piston, cylinder and rings by melting them. Look through the plug hole and see if you see any damage yet, otherwise pull the cylinder head.

Possible Cause #2
The water pump impellar nut has loosened itself allowing the impellar to contact the bottom side of the cover, thus causing it to freeze in place and stopping coolant circulation.

Possible Cause #3
The tunnel edge coolers have worn a hole in them at a contact point between them and the tunnel edge, and allowing coolant to escape unnoticed.

Possible Cause #4
Lack of ice scratchers and running on dry or nearly dry trails, or too many holes in the track that reduce cooling efficiency, or a taller lug height than 2" in combination with any item listed previously.

Possible Cause #5
Spring or summer riding when air temperatures are above freezing.

Possible Cause #6
The coolant bottle lip has become mishapen and can no longer seal at operating temperatures, thus reducing the pressure in the entire cooling system.

Possible Cause #7
One of the bearings has frozen up in the water pump.

Possible Cause #8
Whoever reassembled the water pump last, did not allow enough clearance between the casing and the teethed pulley wheel that fits over the water pump axle, thus freezing up the water pump.

While your fixing things, don't forget to pull of the black plastic rear side covers and see how badly the tunnel is cracked at the end of the coolers. It requires some 1/2" x 1/2" x 4" long alum angle and 4 structural rivets per side, to bridge across the crack. Drill a hole in the end of the crack to relieve crack growth pressure.

I might of missed this but,I had amysterios leak,borrowed a buddies coolant system pressure tester(snap-on)removed radiator cappressurised found one spot weld on front cooler cracked,removed cooler tig welded retest, Done