Thank you for your post...very timely for me. I have a 2008 Saturn Outlook and have been towing a Fleetwood folding camper. Traded in the Fleetwood on a Jayco Ultralite X20E. The Fleetwood weighed 3500 pounds and the Jayco's empty weight is 3900 pounds. I purchased the Jayco near Annapolis Maryland and had to cross the Bay Bridge to travel home to Delaware. It was a very hot day, 99 degrees, and as I went up the fairly steep grade of the bridge my temperature gauge went to nearly 260! After I got to the top of the bridge and started down the temperature returned to normal. I'm concerned because we camp in the mountains and I would never make it to the top of a mountain if I can't even go over a bridge. The water pump on my vehicle was replaced with the recent recall and my transmission has been services also at the local GM dealer. My vehicle is supposed to be able to tow 4500 pounds. My local dealer thought the wind resistance on the new camper versus the folding camper might account for the difference? The red light didn't come on so the engine temperature wasn't at the critical level but it was hot! Any suggestions would be appreciated.