52Carl and all,
I appreciate your interest but I'm beginning to suspect that my situation is a bit unusual as I'm working the truck harder than maybe GM intended. It's set up as a long-haul highway truck with an overdrive. Please read on.
I don't need high airflow, let's say, at highway speeds on flat ground or rolling terrain. Or in winter -- most of the time.
I've run just an electric fan at times and found that it only goes on midway up a long grade or at city speeds (the fan switch goes on at 210F, off at 190). It's in summer on long grades when loaded that the electric isn't enough.
So here's an example -- Every December we leave Seattle loaded with the 11 ft. camper (3600 lbs.) and it's 35 deg. We're headed for LA. There's lots of flat, flat, ground for 300 or so miles till you get south of Eugene OR. Don't need a fan at all. Then you hit the mountains of southern Oregon. As long as it's cold you still don't need much of a fan. Then you hit the Siskyous (serious 7% climb for miles). Still no problem in winter. But then after hundreds of miles of flat through the California Central Valley, and you're pretty tired of listening to the fan, you Hit "THE GRAPEVINE" just north of the LA basin. It's rarely cold enough that you don't need some serious airflow. It was in the 70s last winter when we went over. One year I stopped at the RV park 50 miles north of the Grapevine and put on the mechanical fan I had brought with me. I can do it in half a hour but it's a hassle I can do without, especially when you want to be through LA before 2PM. This is not an unusual problem all over the mountainous West.
