Spark plugs - why you should replace them

Most motorists assume that when they send their car in for servicing, a few things will be replaced. These 'things' include the engine oil, oil filter and perhaps the air filter.

Spark plugs also need to be periodically replaced. Their recommended replacement schedule can be found in the owner's manual.

Now, if your car 'still runs fine', you might be wondering why you need to spend extra money replacing them. Your engine might sound okay, but it may not be fine for long. Torque's resident engineer, Shreejit Changaroth, explains the importance of spark plugs and why they cannot be overlooked.

What do spark plugs do?

In an internal combustion engine, the spark plugs are responsible for igniting (or 'sparking') the fuel-air mixture in the cylinders.

This ignition happens when electricity arcs between the two electrodes found on a spark plug. The current is supplied by the car's electrical system.
 
 
How do they get worn?

As small and insignificant as they may appear, spark plugs have an extremely tough life.

As the igniter of the air-fuel mixture, they must be rated for between 20,000 and 30,000 volts, depending on the type of ignition system.

At the same time, since part of the plug protrudes into the combustion chamber, they endure sudden and extreme variations in pressure and temperature when the mixture ignites and an 'explosion' occurs in its vicinity.

Hence, even if your car starts and runs fine for the moment, spark plugs do have a life span.

The maintenance schedule recommends a change long before your engine starts to misfire prior to total spark plug failure.

As far as possible, stick to the original type of spark plugs as stated in the owner's manual.

But if you do insist on the iridium-core version which may not necessarily improve the performance of your engine, make sure an equivalent to the original is available.

This information should be provided by the maker of the spark plug.
 
 
Here are some other technical advices that might interest you

6 types of car performance modifications to make your car faster on the track
 
Is it important to service your car on time?
 
These boy racer mods are making your car worse
 
 
Is your car long overdue for a spark plug replacement? Check out these highly recommended repair and servicing workshops that can replace your car's spark plugs!