Ford Truck Enthusiasts Forums - GUIDE: How to remove the Water Pump in a 1990-1997 4.0L OHV V6 Ford Aerostar

This guide developed working on my 1990 4.0L XL, which is part of the 1990-1997 series, so theroretically most if not all should also apply to ANY 4.0L V6 Van of that production period.

If you follow this guide, you will (in contrast to other guides of this job) NOT have to remove Alternator, Power Steering motor, Radiator, and Radiator fan shroud.

Some parts of this guide might sound familiar if you've done some homework already because they were taken from existing guides when they proved correct. I decided to write this guide because ALL of the guides out there have errors, some of which are severe (like lumping together 3.0L and 4.0L...) - and NONE of the guides was succinct enough to walk me all the way through.

Required tools & utilities:

K-D Tools KD 3472 – Universal Pulley Holder / 36mm Fan Clutch Tool Kit (recommended quality-level tools)
½”, 5/8”, 10mm wrenches + ratchet(s) w/ these sockets
LOTS of ratchet extension & adapters..
Pipes as extensions
Flat-head screwdriver
Hose clamp pliers
Gasket remover solvent, razor blade scraper, Scotch-Brite Ultra Fine Hand Pad
Bright light or at least headlamp

During the job process on my 1990 model with one serpentine belt, ALL nuts turned out to be "normal" right-hand thread and loosened counter-clockwise. Each model’s fan clutch thread rotation should be imprinted on top of the fan shroud.
1. Remove the air hose going to the throttle body. The small hose towards the passenger seat simply pulls out.

2. Place the fan clutch pulley holder onto the nuts of the fan clutch pulley, then place the fan clutch nut removal tool around the 36mm fan clutch nut. To easier loosen the nut, best use a pipe which you push over the nut removal tool handle for better leverage. Hold the pulley tool with one hand, and push the pipe with the nut-tool inside with the other hand, apart from each other. This is better than shock-hitting the tool with a hammer to open it.

3. Once the nut is loose, you should be able to simply spin the fan loose off the pulley bolt thread by rotating it counter-clockwise.

4. Push the fan carefully toward the radiator to give you a little more room. You can take a sponge or similar to stuff it between fan top and shroud to fixate the fan, to create as much space to work as possible. This approach will keep you from having to remove the alternator and bracket.

5. Draw yourself a diagram of ALL the pulleys, and how the serpentine belt runs around them.

6. Put a 5/8” wrench onto the bolt of the belt-tension retaining pulley (the one underneath the lower right of the alternator, erroneously called “idler pulley”). Shove a pipe over the wrench at around the 11 o’clock angle position. Push the pipe down. That will pivot the idler pulley down and loosen the belt tension so you can slide the belt off the alternator pulley.

7. Push the belt away from the water pump area in way which creates most space around it (no need to pull out the belt completely).

8. To remove the four bolts that hold the pulley in front of the water pump, again use the pulley tool, and a ratchet with a ½” socket: hold the pulley in static position by grabbing two nuts with the pulley tool, and do the initial loosening of the next accessible nut with the ratchet - again with the "refined shock-and-awe brute-force technique”. DO NOT LOOSEN ALL THE WAY – ONLY WORK THE RATCHED UNTIL THE NUT HAS STARTED TO TURN!

Now rotate the pulley 90°, grab the next two nuts with the pulley tool, and the next tight nut with the ratchet. Continue until all 4 nuts have come loose. Once the 4th nut is loose, you can put the pulley tool aside, grab the pulley with your hands, and loosen then remove all 4 nuts 1 x 1. Store these nuts safely, e.g. in a zip-lock bag or closable container.

Pull the water pump pulley out of the engine compartment.

9. Remove the hoses from both sides of the water pump:

To loosen the lower radiator hose to the right, squeeze the hose clamp together (best with clamp pliers, otherwise with vice grips), push the clamp away from the pump down the hose, then carefully use a flat head screwdriver to push the hose off the pipe end on the pump.

The smaller heater return hose on the left side is held with a screw clamp. I was NOT able to get that hose off at this point.. so if you don’t, either – no worries - simply catch up AFTER unbolting the water pump.

10. Remove all 12 same-length 10mm bolts that hold the water pump onto the engine using both, ratchet and wrench, whichever most convenient, working from both, above and below the engine. Be patient, and enduring.. ;)

Once ALL bolts are loose, the pump should come off simply by pulling it towards you using your hands best wearing gloves, or if needed by carefully prying with a wide flat-head screwdriver where the top of the pump protrudes a bit.

In case the small heater return hose is still connected, you need to pull if off now. I had difficulties getting it off, but a combination of WD-40, flat-head screwdriver, and lots of twisting and turning did it somehow eventually.

11. Carefully pull the water pump out of the engine compartment, which might take a few twists and turns around the shroud and the AC hoses.

12. Now there is enough space to pull the fan/ fan clutch combo out – WITHOUT removing the fan shroud! Do this carefully and slowly – wiggle it out inch by inch whilst pulling the shroud top towards you to keep the clutch teeth from getting caught in the shroud plastic.

Inspect the fan! If it has cracks, you need to get a new one! Cracked ones damage the water-pump with their uneven spinning, and are bound to explode apart eventually, which is likely to cause A LOT of DAMAGE under the hood …

13. Remove any remnants of gasket on the edge rim of the water-pump’s engine part of the housing with gasket remover solvent, a razor blade scraper, and Scotch-Brite Ultra Fine Hand Pad (from 3M or similar)