Running flex fans for over 30 years.Never had any problems.I did have 2 factory fans break.My stainless is rated to 12K and been on for at least 15 years.My 440 runs at 180 allday even with a never touched 65 radiator.Ive seen more people have problems with clutch fans than any other type.One flex I ran on my jeep ran probally 70K and a lot of that was plowing snow and off road.Rocky