The 62's temp guage was acting strange the other night. I was on a 30 mile drive in 40 degree weather. Guage read normal through the "warm up" the first few miles. I then noticed that is was fluctuating in a weird manner. It is normally rock solid after warm up no matter if it is winter, summer, up hill or down. But this time is would move up toward the "red zone" quickly then back down in a matter of say 5-10 seconds. This seems way too fast to be an accurate reading. I have seen sending units react to air bubbles in this manner, but I checked the system and found it to be full and the hoses to be firm with coolant. I don't think there is air in there, but it could be a possiblity. What do you guys think? Normally when the TSU goes bad it either doesn't work or pins in the "red zone" I've never seen it "bounce" back and forth from normal to hot. What gives?