Hint: I'd recommend replacing one spark plug at a time to reduce the risk of dropping something in to the cylinder head.
If the old spark plugs are dark grey or black, the engine may be burning oil and should be checked out by a professional.
The original spark plugs on this 2011 Ford Escape XLT were branded "FoMoCo" (Ford Motor Company) part # ILTR5A-13G. 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.
Hint: 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%.
The new spark plugs should be pre-gapped at .052" from the factory. Do not adjust the gap of iridium spark plugs.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".
Note: If you choose to use a torque wrench, tighten the new spark plugs to about 8-10 ft lbs if you used anti seize or 10-12 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.
Push the power connector plug back in place on the top of the ignition coil.
P.S. 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
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