GMC Repair: 2002 GMC Envoy Clutch Fan Trouble, clutch fan, fan clutch

Question
Hi Jeff,

As a former mechanic I know better than to just start changing parts.  My wifes Envoy has the clutch fan engaged all the time which results in a noisy fan and loss of power.  Is this something I should just go buy a new fan clutch and install or are there other items (electronics) I should be checking first.  She just got in the car and started it and it has been engaged fully ever since regardless of speeds or engine temps.  25,000 miles and no previous history of trouble.  Engine is the straight six.

Secondly I heard that changing the clutch requires a special tool ?  Maybe you could comment on this.

Thanks for any knowledge you can share!

Mike

Answer
Mike,
Is this a clutch fan or an electric fan? A clutch fan will run all the time. An electric fan will only run when needed. For the electric,
First off I would change the fan relay. That could be sticking closed causing the fan to run all the time. This would be the cheapest route. If the fan still runs constantly then the fan motor could be bad.
If it is the fan clutch then you do need a special tool. All it is is a long wrench because you have to hit it with a hammer clockwise to break the nut loose, then you can unscrew it with your hand. Let me know if this helps. Thanks for your question.  Jeff