1991 fan clutch removal fundamentals

[chessman21]

iv determined my 1991 4.0 fan clutch is shot and needs to be replaced. Iv tried to find the "how to" info on this forum and else were but but theres so many years and 3 or 4 differ engine sizes with many contradicting threads for each one i dont know which to go by..

1. Do i have to take the radiator out to start with?
2. Do i take plastic fan blades off before i get to the clutch nut?
3. which way does the nut that holds the clutch to water pump turn to take it off, left or right?
4. How do i hold the pump shaft from turning while turning the clutch nut?

 

[adsm08]

1) No. If you have a full fan shroud you might need to take that out with the fan too.

2) No. You have to get the clutch nut off before you can remove the fan blade.

3) The 4.0 has normal threads on the fan. It goes left to come off.

4) Big ass air compressor, air hammer, and fan nut attachment is one way. Or you can get your hands on a fan clutch wrench set. It will have a piece for holding the water pump pulley while you break the clutch nut loose.

 

[ratdude747]

4. Use a strap wrench on the pulley. Know that you may and probably will destroy it. There also is a way to do it using a length of strip steel and two longer pulley bolts (how my father inlaw did it last fall at least).

 

[chessman21]

thanks for the info.

 

[chessman21]

1) No. If you have a full fan shroud you might need to take that out with the fan too.


3) The 4.0 has normal threads on the fan. It goes left to come off.



The 4 fan nuts or the big clutch nut turns to the left to come off??

i see three 4.0 videos and it shows the clutch nut turning clockwise to come off but they are several year newer trucks.

 

[ratdude747]

1) No. If you have a full fan shroud you might need to take that out with the fan too.


3) The 4.0 has normal threads on the fan. It goes left to come off.



The 4 fan nuts or the big clutch nut turns to the left to come off??

i see three 4.0 videos and it shows the clutch nut turning clockwise to come off but they are several year newer trucks.

Turn the clutch nut the same direction of normal rotation. relative to the pulley, normal rotation tightens the fan, so the opposite loosens it. However, since we care about the nut and not the pulley, this reverses as the opposite is true for the nut, and the opposites cancel. Hence you turn the clutch nut in the direction of normal rotation, and opposite of such to tighten. I've seen fords of both directions, so you'll have to look and see.

 

[adsm08]

1) No. If you have a full fan shroud you might need to take that out with the fan too.


3) The 4.0 has normal threads on the fan. It goes left to come off.



The 4 fan nuts or the big clutch nut turns to the left to come off??

i see three 4.0 videos and it shows the clutch nut turning clockwise to come off but they are several year newer trucks.

Both of those turn left to come off. In case relative perspective is the issue, the fan turns towards the passenger side to come off. Since I have four of these engines at my house right now, ranging in production year from 1992 to 2005 (Two of them are OHC) and I have taken the fan off all of them, and many many more on other peoples' vehicles throughout my career, I can pretty confidently say I know how the fan comes off of a 4.0L engine.

 

[chessman21]

Both of those turn left to come off. In case relative perspective is the issue, the fan turns towards the passenger side to come off. Since I have four of these engines ....

Well guess theres no point in telling you that you are correct on what you allready knew... It says in bold on top of the shroud " clutch is right hand threaded"

Sry guys i havent had the truck that long, i replaced the transmission but havent been under the hood much.. I probably will soon tho, Its got a bad tick under passenger side valve cover,, changed oil then seafoamed it changed oil again then put a quart of Lucas synthetic.. none of that made any differ.. .

 

[ratdude747]

Well guess theres no point in telling you that you are correct on what you allready knew... It says in bold on top of the shroud " clutch is right hand threaded"

Sry guys i havent had the truck that long, i replaced the transmission but havent been under the hood much.. I probably will soon tho, Its got a bad tick under passenger side valve cover,, changed oil then seafoamed it changed oil again then put a quart of Lucas synthetic.. none of that made any differ.. .

I would have said that but I'm not as familiar with the older Rangers (read: pre-1995). Apparently they were putting that in the shroud moldings back then.

Colognes are known for lifter tick issues. You'll need new lifters and pushrods if you want to kill the noise.

 

[firehawk618]

adsm08 is exactly right.

 

[Josh P]

Napa sells the perfect wrench for the fan clutch nut. I used the severe duty fan clutch found on the later 4.0l motor when I replaced the fan clutch on my van.