Just wanted to give an update on my similar problem that was discussed above on this forum. This winter I installed another replacement fan clutch in hopes that the first replacement was defective. I have put about 4,500 miles on it since I replaced it. Initially I thought that the overheating problem was somewhat better but wasn't sure because during most of my driving this spring the ambient air temperature was in the 70's and below. 2 weeks ago I got to give it a good test by pulling the grade north of Bishop during a 95° afternoon while towing a 3,000# trailer. The last 2 years pulling the same grade at about 80° my temps would run between 212-225° and I had to use no more than about 1/4-1/2 throttle to keep it from going higher. This year it never got about 212° and then the fan cooled it down to 206-208° starting about 6500'. I also pushed it much harder than I had before to give it a good test. So I am proclaiming that the problem is solved. One strange thing however that once the fan turned on it never shut off. We camped for 2 days at 8,000' and the fan was on the whole time - not towing, driving flat, uphill, downhill, 1 mile or 50 miles it never shut off and I could not even hear the rpm's of the motor above the roar of the fan. The temps never got above 192 during this time. When I left the 3rd day towing it was on until I dropped below about 6,500' and then I didn't hear it on again until about the same elevation when we were crossing the sierras. It got quiet again on the downhill grade at about the same elevation and I haven't heard it since. Is this normal? I was wondering if in the thinner air it might turn faster and I am just hearing it more but I don't know. Any other thoughts? Anyway for now my overheating problem appears to be solved.
