Best Practices for Replacing Spark Plugs in Older Vehicles
When it comes to maintaining your older vehicle, ensuring that the spark plugs are in good condition is crucial. In this article, we'll discuss the frequency of spark plug replacement, including considerations for vehicles that have been sitting for a while and guidelines for older vehicles.
Replacing Spark Plugs in Older Vehicles
Vehicles in general follow a service schedule for spark plugs, which are devices essential for igniting the air-fuel mixture in the engine. The frequency of replacement depends on the vehicle's age and usage. For a newer car, it is recommended to change the spark plugs according to the service schedule. However, for an older vehicle, especially one that has been sitting and just started up fine after a prolonged period, replacement is even more critical.
It is a good idea to treat the spark plugs of your older vehicle as if they were "old" and beyond the scheduled service interval, even if the vehicle runs fine. Therefore, it is advisable to replace them with OEM (Original Equipment Manufacturer) plugs and start a new service schedule for spark plugs. Additionally, I recommend changing the spark plugs every 7 years or at the service schedule mileage interval, whichever comes first. Regular replacement ensures optimal engine performance and helps prevent issues such as overheating of spark coils.
Spark Plug Wear and Maintenance
Spark plugs play a crucial role in your engine's performance. Over time, the ground strap and electrode will wear out due to the continuous spark and combustion cycles. This wear causes the spark gap to widen. While within the engineered design specifications, a wider gap poses a risk to your spark coil or generator, as it may be asked to produce more voltage to jump over the increased gap. Over time, this increased demand can cause the coils to overheat and potentially open or short together.
Regularly replacing spark plugs is a proactive measure to maintain engine health, especially in older vehicles. A spark plug that is too worn can lead to misfires, poor fuel efficiency, and even engine damage. Therefore, it is generally recommended to change spark plugs every 5-7 years, regardless of mileage, as they are relatively inexpensive and act as a cheap form of insurance for a thorough engine check.
Additional Tips for Removing Spark Plugs
Removing spark plugs from older vehicles can be a challenging task, especially from aluminum head engines. Carbon accumulation can form a ridge on the spark plug threads within the combustion chamber, making removal difficult. Additionally, aluminum cylinder heads have a tendency to bond with the iron or steel threads of the spark plugs, making them difficult to extract without damaging the head. To avoid stripping the threads, a good tip is to add some WD-40 to the spark plug area before attempting to remove them. This helps to loosen the plug and makes the removal process easier.
Furthermore, inspect the bottom of the spark plugs. Ideally, they should be a golden brown color, indicating proper functioning. Colors such as black soot, oily black, or white indicate potential engine issues that require attention. Replacing the spark plugs can significantly improve engine performance, as seen in my work van, which saw an improvement from 13.5 to 15.75 miles per gallon after the replacement.
Contemporary Considerations
It is also worth noting that around 1996, General Motors began using platinum plugs, which can last much longer, potentially up to 100,000 miles. However, this is a subjective opinion and varies based on the specific make and model of the vehicle. Therefore, whether you should change the spark plugs every 100,000 miles depends on when they were installed and the type of spark plugs used.
Regular maintenance and timely replacement of spark plugs are essential for keeping your older vehicle running efficiently. By following a service schedule and replacing spark plugs every 7 years or at the recommended mileage interval, you can ensure optimal engine performance and extend the life of your vehicle.