Originally Posted by
DmaxMaverick
Common misconception. The fan clutch is air-heat-engaged. With little or no (hot) coolant flowing through the radiator, the air passing to the clutch isn't hot enough to engage the clutch. Once the thermostats open enough, it will heat the air passing to the clutch to engage it, progressively depending on the air temperature. At 240, the stats should be full open, and the air passing to the clutch should be hot enough to cause full engagement. This isn't happening if you don't hear the fan when it's that hot.
Cheaper? That's a relative term. How much cheaper is it, if it doesn't work, or doesn't work well enough? It's only a small piece of the puzzle, anyhow. You should be able to source a 2006+ intake system from a wreck for near or below that of an aftermarket kit. The 2006+ OEM system works very well, with little to no improvement from aftermarkets. An added benefit is the filter element required will be for your truck (although for a different M/Y) and commonly available, even if someone replacing it doesn't know of the upgrade. Many of them were upgraded by GM under warranty, so all or most dealerships would be familiar. If you upgrade, you can have the GM vehicle history reflect that, which may add to the trade/sell value.