My truck has it's original flex fan in it, I think. Says GM on it and I don't know many people to replace their GM parts with GM parts. If it is original, the fan is 29 years old and has no cracks in it. It's quiet. I do run a little warm when the temp is around 100 somthing and I'm going over a steep grade with my partially rotted radiator. Maybe 220 or so. But, in traffic the thing cools like a dream. I've sat in 1 stop in 100+ degree weather for 15-20 minutes idling and my temperature went up to 195 or 200. I think it runs warmer while im moving because the fan blades flatten out and obstruct the radiator opening. I know there are some clutch fans that are extremely noisy, the one in my sister's 83 mustang is, the mid 90's explorers have very noisy clutch fans. Clutches wear out, too, and they're very expensive to replace. I recommend you get one of the unequal spaced blade flex fans, they're the quietest. The only time I would not recommend a flex fan is if you plan on doing deep water crossing. Without the clutch, as soon as those blades hit the water you're going to toss your belts.