How to Seal a Cracked Intake Manifold on a Grand Marquis

by Allen Moore
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From the 1996 through 2001 model years, Ford Motor Company installed plastic intake manifolds on their Crown Victorias, Lincoln Town Cars and Mercury Grand Marquis equipped with 4.6-liter engines. These intakes were prone to cracking due to the stresses incurred during acceleration. Ford issued a recall and offered a replacement intake manifold, made of a plastic and metal composite. If you own a Grand Marquis with this issue, it is best not to drive it until you can replace the intake. If you must drive it, however, you can attempt a temporary fix that will keep you on the road for a short time.

Step 1

Make sure the engine is cold before you begin. Once it's cold, spray the engine cleaner on the cracked area and clean it with a rag until no residue, grease or dirt remains.

Step 2

Use the sandpaper to scuff the area well to help the epoxy adhere. Make sure to sand at least two inches in each direction from the crack. Epoxy bonds to an abraded area better than to a smooth area, so the better you scuff it, the better the epoxy will seal.

Step 3

Prepare the epoxy per the directions on the package. It is best to pick up the epoxy from the local Ford parts department, as they have epoxy specially formulated to work on Ford parts. Ask for the diesel gray, not black or any other type of epoxy or adhesive.

Step 4

Apply the epoxy to the area, being careful not to drip any excess down through the crack or onto any other components or accessories under your hood. Diesel gray will last forever, so make sure it does not get anywhere you do not want it to be.

Step 5

Allow the epoxy to cure per the directions on the package.

Top your engine coolant off after the epoxy has cured. Start the engine. Allow the engine to come up to operating temperature and inspect it for leaks around the epoxy patch. If there are none, you can drive the vehicle to the repair shop or gently around town for a few days until you are ready to have the intake replaced.


  • This is by no means a permanent solution. Be mindful of a potential coolant leak at all times while driving with a patched intake manifold. If you see steam coming out from under the hood, stop the car immediately and allow it to cool off. Driving with a coolant leak can quickly cost you an engine, instead of just an intake manifold.

Items you will need

  • Engine cleaner
  • Rags
  • Sandpaper
  • Diesel gray epoxy

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