One problem related to cooling fan has been reported for the 2005 GMC Envoy. The most recently reported issues are listed below.
I have been reading a lot and it seems to be a common problem in the 2005 series GMC Envoy, chevy trailblazer. Basically the cooling fan clutch goes bad easily and quickly. When you start the engine it is fine but after the clutch needs to engage it either clicks, and doesnt engage or it just makes that common jet engine roaring. This is all to common and gm needs to do something about it. There have been people with 40,000 miles or 140,000. I my self am on my second one and it is already doing to the same thing after 5 months.