Ok guys, we need a little help. We got our F7 all plumbed to hook up to our cooling machine. We plumbed into the hose running into the head and removed the thermostat (as recommended by D & D). When we attach the cooler, we can circulate all the hater we want, but we we run it, it will go about 1/2 mile total and the "Check Engine" light starts flashing. When you feel the running board exchangers or the rear exchanger, they are cold. Plenty of loose snow getting to them, not a problem there. We tipped the sled on the PTO side, and lifted the rear of the sled up, and can hear the water bubbles going. We probablly don that 20 times at least, and also did it the way the manual recommends (to tip it over on both sides while the motor is running). Still nothing seems to work. Same thing, go about 1/4 - 1/2 mile MAX, and the heat light is blinking. Come back cool it off, do the same procedures, and nothing seems to work. Any ideas of what might be going on? Why won't it circulate the water? Getting very frustrating. Any help would be appreciated.