I received a question this week from a customer in the Northern Cape, asking how to replace his spark plugs himself. His usual mechanic was hospitalised with Covid, and the next mechanic he “trusted”, he said, was in a town, “aan die ander kant van die wêreld”, 140 kilometers away.
Although we generally do not give advice of this nature, I did feel sorry for the poor customer as it’s a relatively straightforward job. He’d be done and dusted quicker than he’d complete the first pothole-strewn 10kms of his 280km round trip.
When to replace spark plugs
If you check your owner’s manual, you’ll probably find that your automaker recommends that you replace your spark plugs roughly every 50 000 kilometers. That’s fine if you’re using stock spark plugs. However, the actual timing of replacement will vary depending on other factors.
• High Performance: If you have high performance spark plugs, it’s possible that you will need to replace them more often, as the electrode can wear down faster.
• Long Life: Some spark plugs are made to have a longer life. Their electrodes do not wear down as quickly, meaning that you won’t need to replace them as frequently. Look for plugs made from iridium or platinum for the longest life (copper has the shortest lifespan – generally about 30 000 kilometers).
• Oil Leaks: When you pull a spark plug out of the engine, the base should be relatively clean. If there is oil present, it means there’s a leak. Not only does that mean you’ll need to replace a blown seal, but it means your spark plugs will need to be changed more frequently because of contamination.
• High Revs: If you regularly “put your car through its paces,” you’ll put additional wear and tear on your spark plugs, meaning that you’ll need to replace them more often. Drivers with a lighter foot will enjoy longer life from their plugs.
If your engine seems to be running rough, or skipping, chances are good that it’s time to have your plugs replaced. Other symptoms can include rough idling and stalling.
How to change spark plugs
1. Gather the correct materials - To change your spark plugs you will need the following materials: Protective gloves, Safety glasses, Socket and ratchet set, Spark plug gap gauge (optional in most cases), Spark plug socket Spark plug wire removal tool (optional) and a Torque wrench (optional).
2. Locate the spark plugs - They are threaded into the cylinder head and sit underneath the coil pack or plug wire boot. If you are having a difficult time locating the plugs, a repair manual for your vehicle is helpful.


3. Remove the coil packs or plug wires - First, put on the necessary safety equipment. This includes safety glasses. Gloves are optional, but highly recommended. To remove the plug wire, grip the boot and pull up while moving it side to side. If you aren’t careful when doing this the plug wire can tear out of the boot. This job can be made easier with the use of a dedicated spark plug wire removal tool.


4. If your vehicle has spark plug wires, it is a good idea to remove each wire and corresponding spark plug one at at time. This is so you don’t forget the order or routing of the plug wires. Alternately, you can mark each wire with the cylinder number before removal. The bottom line is, engines having a firing order and the plug wires must be re-installed exactly how they were.


5. Remove coil packs - If your vehicle has individual coil packs the job is much easier. To remove the coil packs, start by removing the hold down bolt. This is a small bolt, usually with a 8mm or 10mm head. Once the bolt is moved, pull the coil pack straight up and out of the valve cover.



6. Remove the spark plugs - This step is where the magic happens. Wait until the engine is cool to the touch before doing this. Attach your spark plug socket to the end of your extension and ratchet. Once the engine is cool, insert the socket into the spark plug hole until you feel it grip the top of the plug. You should be able to push the rubber portion of the plug socket firmly over the plug.


7. Turn ratchet - Next, slowly turn the ratchet counter clockwise to loosen and remove the plug. As was stated above, it’s a good idea to replace the plugs one cylinder at a time so the firing order doesn’t get mixed up.


8. Inspect the old plugs - Take a look at the old plugs before you toss them out. Plugs can reveal a great deal of information about the health of the engine. Normal deposits will be light brown or tan in colour. If the plugs are physically damaged, black, wet or white suspect an engine problem.


9. Get the correct replacement plugs - Getting the correct plugs is especially easy nowadays, as we have listed spark plugs by vehicle application on Start My Car. Our friend in the Northern Cape popped onto our website, entered the make and model of his car, and the correct spark automatically came up! If you are buying your plugs elsewhere, it’s a good idea to compare the old plugs to the new ones before installation. All our NGK Spark Plugs have the gap already correctly set.


10. Install the spark plugs - Place the plug into the end of your spark plug socket. Insert the socket and extension into the hole and gently thread the plug into the hold (turn it clockwise). Keep turning it until you feel the plug bottom out.



11. Applying Anti-Seize - Certain mechanics apply a light coat of anti-seize to the plug threads before installation. NGK however, state that this is not necessary and the plugs should be installed dry. Please see the video link in the Summary section, for more information regarding Anti-Seize.


12. Torque the Plugs- Never over-tighten the plugs as cylinder head damage can result. If you are uncertain as to how tight the plugs should be, torque them to specification using a torque wrench. These specs can be found in the vehicle repair guide.


13. Re-install the coil packs or plug wires - To re-install the plug wires, simply place the boot over the tip or the plug and push down. You will know the boot is secure when you hear it click into place. If your vehicle has coil packs, just drop the coil pack into the cylinder. It does not need to click into place. Then, install the hold down bolt and tighten it down.





Worn plugs can cause all kinds of problems including increased emissions, loss of performance, rough idle, hesitation, and hard starting. Exactly how often they should be changed is determined by the manufacturer’s scheduled maintenance table. If you wish to replace them yourself, you can follow the steps above or look online for many good video demonstrations. I found this one https://www.youtube.com/watch?v=0_xGFfketcs particularly helpful.


All the tools required and the plugs are available on Start My Car. If we can get them to the remote dorps of the Northern Cape, we can certainly get them to you!