Fan Clutch stuck on water pump - Chevrolet Forum - Chevy Enthusiasts Forums

Fan Clutch stuck on water pump

Old  November 29th, 2013, 12:10 PM
Fan Clutch stuck on water pump

I've got a slow leak from my water pump, which I plan on replacing. It's slow enough that I can drive it if need by. Although, I'd much rather replace it...and normally,I'd almost be done by now!

I can't get the ______ (fill in your favorite adjective) fan clutch off. I wish it was the four bolts and it falls off, like the pre-'96 models. I have the large nut (36mm), and it won't budge. I cannot get the water pump pulley to not move so that I can break the torque on the fan clutch nut.

I plan on replacing the fan clutch after I install a new water pump.

I tried using a pry bar against two of the four bolts, and it just bent my (1/4") pry bar. I haven't used a screw driver,and after the prybar, I know it would bend too.

Do you all have any ideas on how to get the fan clutch off of the water pump? Looking at the new water pump and fan clutch, it appears to be standard threads (lefty-loosey/righty-tighty is what I teach my students who don't know the direction for standard threads).

Unfortunately, I cannot find a 36mm wrench. I've relegated to using an adjustable wrench.

Any ideas?


aka: Warthogcrewchief

Old  November 29th, 2013, 2:59 PM
I was able to get the fan clutch off and the water pump was a piece of cake. I found a youtube video on the fan clutch/water pump removal. They used a hammer on their adjustable wrench. So I pulled out my BFH (3 lb. sledge) and lightly tapped on the adjustable wrench. It required sharp blows to break it free, not constant torque.

Old  November 29th, 2013, 7:40 PM
  • Administrator
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    KC, MO area
Glad you got her broke loose. Did you use any Kroil or other penetrant?

Old  November 30th, 2013, 1:34 AM
Negative. I considered using PB Blaster, but since the nut was shrouded, it would have been difficult for any penetrating fluid to get to the threads.

The problem I was having was that the pulley would spin under the belt due to the torque I was using to break the nut free. Quick, sharp blows with a hammer is the way to do it. It's also best to have a wrench that will clear the fan blades.

I got a great deal on two adjustable wrenches for $14 at Home Depot. Both are big enough to fit over the 36mm nut, but they're pretty short - 8" and 10". I'd recommend at least a 12"-14" wrench length to clear the fan blades. A longer handle would make the job just a little easier.

Edit: I also placed a small amount of anti-seize on the threads of the water pump bolts (required!) and the fan shroud nut (not required). Anti-seize is designed especially for steel bolts going into aluminum components (engine block). It prevents the threads from galling or bonding together. It'll make the job easier next time.

For threads (bolts, spark plugs, etc) that are installed into metal (especially aluminum), the threads of the aluminum can gall and get "torn" out of the surrounding surface due to the metal bonding due to expansion/contration due to heating/cooling and being installed for a long time.

I have that problem now on a motorcycle that I own. My father had spark plugs installed in his (now mine) bike a few years back. The shop did not use anti-seize, and now the spark plugs do not get tight. I'll have to install heli-coils on the spark plug holes when I do an engine rebuild in a few months.

Last edited by warthogcrewchief; November 30th, 2013 at 1:44 AM.
Old  November 30th, 2013, 10:03 AM
  • CF Junior Member
    Join Date: Nov 2013
    Posts: 42

I have a piece of about 1" pipe 18" long that I call the persuader.It slips over most wrenches to give you that extra boost. It comes in handy especially when removing brake caliper mounting bolts. I guess that's why they call it "Loctite" because it does!!!!

Old  December 1st, 2013, 12:54 PM
Yep, I have three 1"x12" pipe and two 1"x18" pipe, plus the adapters to connect them all together. I also have a 1-1/4" pipe 6" long plus the reducer to connect it to the 1" pipe because sometimes the tool handle doesn't fit into the 1" pipe.

I tried using the pipe first time around on the fan clutch nut. I had plenty of torque. The problem was that the drive belt did not hold the the water pump pulley in place.

I used the hammer/wrench to break it free using quick blows.

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