Spark Plug: Description and Operation

Spark Plug Showing Coated Insulator:

The spark plugs used on the 4.9L engine have platinum pads welded to the electrodes. These pads extend the spark plug life to 100,000 miles.

All 4.9 Spark plugs have a lubricative boot release coating baked onto the outer spark plug ceramic. This coating is clear with a slightly waxy feel. The coating helps prevent the silicone spark plug boot from sticking to the spark plug ceramic. This greatly reduces the effort required to remove and install the spark plug boot.

CAUTION: It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a nonhazardous material and incidental contact will not cause any adverse effects. However, exposure to polymer vapors - the result of contamination of cigarette products and subsequent burning of the polymer - may result in flu-like symptoms and should be avoided.

4.9L spark plugs are a resistor type tapered seat design. No gasket is used on these tapered seat plugs.

Normal service is assumed to he a mixture of idling, slow speed, and high speed driving. Occasional or intermittent high speed driving is needed for good spark plug performance because it gives increased combustion heat that bums away any excess deposits of carbon or oxides that have built up from frequent idling or continual stop-and-go driving. Spark plug type is 41-902 and gap size is 0.060 inch. Always replace plugs with current one listed.