how do i replace the clutch fan on a 91 f-250 351 4 x 4 no ac auto trans

 

I did mine a couple months ago. 1990 F150 no AC. Will be the same on your truck.

First remove the belt. I dont remember if I removed the fan shroud before or after removing the fan. The shroud only has two bolts so no big deal. Then you'll have to remove the fan from the clutch (4 bolts I think) and pull the fan/shroud out of the engine compartment. Then another 4 bolts hold the clutch to the engine. There is a pulley between the water pump and the cluch, so make sure no to drop/loose it. Installation is the reverse. It's actually very simple. Make sure to put the belt back correctly.

You'll need a wrench for the belt tensioner to remove the belt (5/8 I think). And the fan and clutch both use the same wrench, 7/16 I think.

If you just examine the whole setup you'll see how it all goes together.

 

You shouldn't need to remove the shroud. Unbolt the fan, then the clutch. Then you can get the clutch out and leave the fan sitting in there. Put the new one in and bolt it all back together.