The air cleaner assembly (airbox) found on '91+ Town Car and '92+ Crown Victoria / Grand Marquis are prone to warpage which can allow the air filter to fall and let unfiltered air enter the intake tract. This is more prevelant with higher mileage and age, especially in hot climates due to radiant engine bay heat distorting the plastic.
This article describes an easy fix for this concern using basic, readily available hardware store parts.

The following article was authored by Fordiesel69 and has been converted into UBB format

Panther Warped Air Box Repair

Authored by: Fordiesel69

Email: [email protected]

Applies to:
1992 – Current Crown Victoria
1992 – Current Grand Marquis
1991 – Current Town Car

Introduction: This article will detail the removal, repair, and replacement of the lower air box assembly. During which, you will reinforcing the factory air box to correct the distortion, and prevent it for occurring in the future. This job is very easy and anyone who can change oil can do this.

Issue: Ford decided it was only necessary to have 2 latches holding the upper lid to the lower air box. Over many years of tension and temperature extremes, the lower airbox can distort allowing the air filter to fall down inside. Leaving this issue uncorrected will result in; higher than normal engine wear, fouled MAF sensor, higher than normal silicon reading in your oil samples, and could eventually result in the engine needing replacment.

Parts Needed:
  • (1) bag or (8) #8-32 Nuts.
  • (1) bag or (8) #8 Flat Washers.
  • (2) 1 Foot pieces of 8-32 allthread
  • Green Penetrating Loctite

Tools Needed:
  • 7/16 ¼” Drive Deep Socket
  • ¼” Drive 12” extension.
  • ¼” Drive Ratchet.
  • 2 Pairs of pliers.
  • Drill bit the size of the allthread.
  • Corded or cordless drill.
  • Hacksaw & vise (optional)

  1. These are the parts needed to do the repair.

  2. Remove upper airbox lid and set aside. No need to disconnect anything unless you feel it makes it easier on you. Then remove the 2 nuts shown in red. It’s a good idea to spray with penetrating fluid to reduce the risk of snapping them off.

  3. Remove the remaining nut shown in red. More than likely you will feel some serious resistance, then all of a sudden it will become free. This nut will seldom come loose, rather the rubber mount breaks in two. No biggie, a replacement can be purchased if it really bothers you. The other two mounts are plenty.

  4. Shown here is the warping that allows the air filter to fall down inside the airbox.

  5. From here you can see the middle is kind of spread open. This will be corrected by inserting allthread and a combination of nuts and washers to draw the plastic back in straight.

  6. No need to be real precise about drilling these holes. Start on the side housing the latches, and drill as pictured below. This is about the height you want them, any higher and they will interfere with the air filter media.

  7. On the side opposite the latches, also drill 2 holes as pictured below.

  8. Turning the airbox over, insert the allthread into the air box, and put the nuts and washers on in this order: washer – nut – nut – washer. Leave a little on the end to stick thru to the outside of the airbox.
  9. Once thru, go ahead and place a washer, then a nut on the end as pictured below.
  10. Tighten or loosen the interior nuts as pictured below, do not worry at this point about making final adjustments to this allthread. You will do that last.

  11. Repeat procedure for the next allthread, and assemble the nuts and washers as shown.

  12. Go ahead and make your final adjustments to remove the warp from the airbox. Tighten the nuts with 2 pairs of pliers. Hold the interior nut and tighten the outer nut until snug. Do not over tighten or the air box may crack. After you have them adjusted and tightened, cut off the excess allthread using whatever means you find necessary. I used a hacksaw.

  13. Place one drop of green penetrating type loctite on each of the nuts, both on the inside and outside. This will prevent them from loosening.

  14. Finished product!
  15. Verify the air filter fits correctly. If the filter pleats hit the allthread, simply pry them open in the appropriate two spots. If you are using certain brands of filters with a metal bar keeping the pleats secure, you may need to use another brand of filter, or make modifications to allow it to fit. Lastly, reinstall the lower air box onto vehicle, and reassemble.

Conclusion: Overall, this is the way I chose to do this repair. Some might find this “hack” and prefer to simply buy a new one. That’s fine, but it will also warp over time just like the old one did. The allthread can interfere with the pleats on the air filter, so do your homework BEFORE doing any drilling. Also make certain not to cut your allthread prior to assembly, although tempting, you will have major difficulty threading the nuts on the end you cut off.

As always, feedback is most certainly encouraged, whether it is good or bad. Let me know if you want something changed or find something just isn’t right. Email: [email protected]

-----Courtesy Fordiesel69

Edited by dRock96Marquis (03/10/09 01:39 AM)
Edit Reason: Images hosted to CVN
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Former owner of a Grand Marquis with a few mods, Grand Marquis "LSE S/C"