Don't shut it down right away. This stops the fan turning, and keeps the waterpump from circulating the coolant away from the block and through the rad. If you're on hand of overheating, I'd pull over, idle (maybe even set the hand throttle up to 1200 or so to let the alternator keep up) and turn the heater fan all the way to high, on the highest temp. This will bleed off some of the heat from the engine, into the cabin. Oh, and if its a nice day, get out... <img src="/forums/images/graemlins/scared.gif" alt="" />

I once drove from Nfld to Calgary in Betsy II (3.0V6) towing a trailer. Temp gauge was starting to climb, so I pulled over when I got through the worst of Montreal traffic, at a rest stop, and was just breathing a sigh of relief after I shut her down, when I saw steam coming from under the hood. Shoulda left it running... <img src="/forums/images/graemlins/baby.gif" alt="" /> After she cooled down all the way and I topped off the water, I did make it the rest of the way west, but I could've avoided the overheat if I'd let her idle for a few minutes. Lesson learned.