Water pump pulley fan clutch nut off?

Tiny
PACKERS27
  • MEMBER
  • 2000 GMC SIERRA
  • 5.3L
  • V8
  • 2WD
  • AUTOMATIC
  • 325,000 MILES
I'm having a very very hard time getting the fan clutch nut off of the pulley. Some people say that you turn it clockwise and some people say you turn it counterclockwise but the way the fan blades look, it looks like you turn it clockwise to loosen it. I cannot for the life of me loosen this nut. I cannot find a pulling range at any parts store. This pulley has four holes in it and supposedly it fits an M8 so you can use a long screwdriver or a pry bar to hold it while you try to turn the nut. I've also tried to put some heat to the nut and still didn't work. I've tapped my wrench with a hammer to try to shock it but nothing works. I even tried turning it counterclockwise and it still won't budge. I cannot hold the pulley well enough to even try to make a real effort to turn the nut. Strap wrenches doesn't work either. Well the Robert ones don't. My question is, it is reverse thread and you go clockwise to loosen it right? Also do you have any ideas on how I can get this fan clutch nut off? I'm changing the water pump
Friday, December 12th, 2025 AT 2:38 PM

5 Replies

Tiny
STEVE W.
  • MECHANIC
  • 15,268 POSTS
Should go counterclockwise to remove the fan. I normally use a tool that grabs 2 bolt heads and then a large wrench. The wrench gets put on and smacked with a mallet to break the threads free. They are constantly being tightened when the engine is running and they get TIGHT.
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Friday, December 12th, 2025 AT 3:22 PM
Tiny
PACKERS27
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Is there a way to know for sure which way it loosens? I've smacked the wrench a few times and also put heat to it. It just doesn't budge AT ALL
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Friday, December 12th, 2025 AT 5:20 PM
Tiny
STEVE W.
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Yes, it turns lefty, counterclockwise to loosen. They usually require a good hit to break them free at the best of times, they do use blue loctite on them a lot so between the normal torque and that they are usually pretty tight to get moving. One trick you can try, take a solid piece of steel like an extension or drift, set the tip of that item on the edge of the flat that retains the clutch. Like you were trying to shave the corner off the nut. Now give it a HARD hit with a hammer. OH be sure the belt is still on as you can't hold the pulley at the same time.
Like this - https://www.youtube.com/watch?v=AK-J1ZUATyg

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Friday, December 12th, 2025 AT 5:53 PM
Tiny
PACKERS27
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I never thought of that. Ill give that a try. Do you think heating up the nut helps as well? Also, the holes on the pulley is not M8x125 like chatGPT says. Its smaller. Do you know what size those holes are.
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Friday, December 12th, 2025 AT 5:59 PM
Tiny
STEVE W.
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It's been a while but I think they were M6, right around 1/4" in SAE.
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Friday, December 12th, 2025 AT 8:03 PM

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