Owners of other Ford or Mercury vehicles with the Duratec 25 engine such as the Fusion, Milan, and Transit Connect may also find these DIY instructions to be helpful.

The items needed to complete this procedure include an 8mm socket, a 1/4" drive ratcheting wrench, a 5/8" spark plug socket, a 6" extension, a 3/8" drive ratcheting wrench, anti-seize lubricant (optional), dielectric "tune up" grease, and a spark plug gap gauge.

The original iridium spark plugs included with this 2011 Escape are the NGK 3811 (also known as part number ILTR5A-13G).

Other plugs compatible with the Duratec 25 engine include the following: Bosch 96302, NGK 5019 (LTR5GP), NGK 4344 (LTR5IX-11), ACDelco 17, Denso (4718) ITV16TT, Champion RE10PMC5 (3032), Autolite APP5363 and Motorcraft SP-530.

Then press the release button on the power connector attached to the top of the ignition coil and slide it straight off.

Use the 8mm socket and 1/4" drive ratcheting wrench to remove the screw that holds the ignition coil to the top of the engine. Set it aside in a safe place.

I'd recommend replacing one spark plug at a time to reduce the risk of dropping something in to the cylinder head.

Twist the ignition coil back and forth a few times to make sure that the rubber dust boot is not stuck to the tip of the spark plug.

Attach the 5/8" spark plug socket to the 6" extension and the 3/8" drive ratcheting wrench.

Carefully lower the spark plug socket and push it on to the tip of the spark plug. Rotate the ratcheting wrench counter clockwise to loosen the old spark plug.

Once the spark plug is loose, detach the ratcheting wrench and spin the plug out by grasping the end of the extension.

If the old spark plugs look white, they may have been exposed to high temperatures such as engine overheating or they are the incorrect heat range for your driving conditions and/or environment.

If the old spark plugs are dark grey or black, the engine may be burning oil and should be checked out by a professional.

They are actually manufactured by NGK and the part number is the same as the NGK 3811 (ILTR5A-13G) Laser Iridium spark plug.

Iridium spark plugs may seem expensive compared to the cheaper copper, nickel or platinum plugs but they can easily last up to 100,000 miles. Cheaper plugs will need to be checked frequently and changed at much shorter intervals.

Most spark plug manufacturers such as NGK recommend that you should not use anti-seize lubricant on the new spark plugs since it can lead to over tightening.

But many people insist that applying a tiny amount of anti-seize to the threads of a new spark plug can make it much easier to remove if it is not replaced again for 100,000 miles.

If you do apply some anti-seize to the threads of the new spark plugs, be sure to use only a tiny amount and wipe off any excess with a paper towel. Avoid getting anti-seize grease near the tip of the plug.

Then also take care to not over tighten the plugs by using your "mechanic's feel" or reduce the torque value on your torque wrench by 20%.

If you have a spark plug gap gauge, verify that the gap on each new plug is .052". The Ford Escape owner's manual lists the acceptable spark plug gap range as being 0.052" to 0.056".

Securely insert the new spark plug in to the end of the spark plug socket. (Your spark plug socket should have a rubber insert or magnet to hold the new plug in place.)

Gently lower the spark plug down in to the well by holding on to the end of the 6" extension piece. Try to avoid hitting the tip of the new spark plug on the metal cylinder head.

Spin the extension and socket clockwise by hand to prevent the new plug from becoming cross threaded. Once the spark plug stops spinning and makes contact with the cylinder head, attach the ratcheting wrench or torque wrench.

Slowly tighten the spark plug with the ratcheting wrench until you feel the crush washer at the tip of the plug compress.

Once you feel the crush washer compress, tighten the spark plug a small fraction of a turn past that point. Do not over tighten the spark plug. Over tightening the spark plug may strip the aluminum threads.

If you choose to use a torque wrench, tighten the new spark plugs to about 10-15 ft lbs if you used anti seize or 15-20 ft lbs if they are "dry". I'd recommend just tightening the plugs by hand so that you can feel when the crush washer compresses.

Apply a small amount of dielectric grease or "spark plug boot lube" to the opening of the rubber dust boot on the bottom of the ignition coil. This will help prevent it from becoming stuck to the new spark plug and keep out moisture.

Carefully lower the ignition coil down over the new spark plug and twist it a few times to spread the dielectric grease.

Insert the screw and tighten it with the 8mm socket to secure the ignition coil in place.

Push the power connector plug back in place on the top of the ignition coil.

To test the new spark plugs, start the engine and listen for any strange sounds that may indicate a problem.

I'd recommend checking that the spark plugs are still tight after the vehicle has been driven a few 100 or a few 1000 miles.

For more, please check out my other Ford Escape Repair & Maintenance Guides.