Well I put on 150 miles last weekend trouble free. Last night I went 25 miles got to the first town road 6 block and the temp light came on. So the overflow bottle was to the top but not overflowing yet. Plugs where dry. After sled cooled down overflow bottle had the normal amount of coolant. Cylinder 3 plug was black and fouled out sled was not running quite right but ran good. So this morning I changed the one plug sled runs better. Took the radiator cap off to see if I could see coolant flowing. I really could not tell. So how do you check the water pump or where should I go from here?? 
