Automotive Spark Plug Service Life & Maintenance Practices

The spark plug is the fire starter of your engine. Without properly working and cared for spark plugs how on earth can you expect your vehicle to drive smoothly drive down the road or highway and give you adequate and acceptable miles per gallon of gasoline fuel driven? Yet few motorists give their spark plugs short shift – that is until their vehicle won’t start in the dead of a Canadian winter or their fuel usage is just horrendous. So goes life and the treatment of spark plugs in automobiles.

Spark plug service life can vary overall a great deal depending on such factors as automotive engine design and designs themselves, type of ignition system installed and used ( electronic ignition or older types of points and breaker points), type of service the vehicle is used for generally , driver habits and even type of fuel used.

Under extreme cases, some sparking plugs may require replacement at 5,000 miles (equivalent to 8,000 kilometers). Others may last well beyond the often recommended replacement intervals of between 15,000 to 30,000 miles (that is 24,000 to 48,000 km) for newer more modern, and more popular on the road – electronic ignition system types.

In deciding whether to clean and reinstall or replace the plugs, the mechanic or do it yourself mechanic should weigh the costs and time of service for cleaning, filing and gapping the plugs in remains of useful life left for the units at hand.

Overall – and not only for reasons of reliability and service , it is often an automotive truism based on year and miles of mechanic’s experience and experiences that unless the plug or plugs are in truly sound condition then it usually the best choice overall to spring for new plugs. Costs for replacements are usually quite reasonable especially in this day and age of high fuel and gasoline costs.

What though are recommended spark plug cleaning intervals? It can be said that when spark plugs receive periodic cleaning and gapping that they will overall function better and will last longer – both in terms of time and miles distance. Generally it would be sound to say that a reasonable course of action is to have plugs cleaned and inspected in the ranges of approximately every 10 to 15,000 miles (equivalent to approx 16 to 24,000 km in metric terms.)

Lastly how do you as a mechanic – either amateur or professional examine spark plugs? A careful study of the spark plugs is helpful in determining engine condition, plug heat range selection and trouble resulting from operational conditions.

In normal cases how does a spark plug appear then? It can be said that a spark plug operating in a sound engine, at the constant temperature will have some “gray deposits”. Deposit color will range from tan to gray in appearance and appearances.

Electrode gap will show growth from about .001 (0.025 mm) per 1000 miles driven, but there should be no evidence of burning what so ever.

Lastly features to look for and exhibit in pathological spark plug appearances and engine situations include – fuel fouling , oil fouling , splashed fouling , aluminum throw off and lastly what is termed in the automotive trades “scavenger ” deposits.

Author Bio: Kenny I. Vessel Auto Trader Research Info Capital Car Carriers Most Capital Car Carrier Transport