Picking the best spark plug for your car
When it comes to choosing the correct spark plug for your car, it’s not always as simple as you’d think. They come in various lengths and gap sizes, are made from different core materials and are manufactured to operate at different temperature ranges.
Why isn’t there a single, simple universal option? Because car engines come in all sorts of shapes and sizes, built for different types of driving.
The perfect spark plug for your car is the one designed to run specifically with your engine. So, as with all the parts your car relies on for its optimum performance, how do we find out exactly what that is?
How to find your perfect spark plug
1. Check your owner’s manual
Given that each engine is designed to operate under fine tolerances, the safest hands to dictate your vehicle’s spark plugs should be its manufacturer. Your owner’s handbook or manual should detail the type of spark plug recommended for your car, including the part number.
However, tracking down new spark plugs from such codes or settings isn’t always easy, with so many brands of spark plugs and alternative upgrades on the market.
2. Locate the metal information tags on your car
If you’ve lost your handbook (or never had one in the first place), lift the bonnet of your car, and you should find a metal plate near the radiator or fixed under the bonnet. This panel features information about the vehicle, including the model number or VIN (vehicle identification number). You can use these codes to identify the parts for your particular car and cross-reference them with supplier tech-spec sheets.
3. Supplier guides and specification sheets
Most auto-centres will have flip charts or posters detailing the different spark plugs they sell for each vehicle. You’ll need precise information for your make and model to ensure you track down the correct plug for your engine.
4. Use online checking and compatibility tools
Checking codes against booklets and flip charts seems quite antiquated in today’s digital world. So, just as you’d expect, there are plenty of digital and online ways to track down the appropriate spark plugs for your car.
Most online tools and checkers pull up a list of appropriate plugs simply by having you enter your car registration number. Others will ask you to select your make and specific model, engine size, and year from the relevant drop-down fields before delivering your options.
5. Ask an expert
There’s more than one way to skin a cat, as the saying goes, and when you pump your details into any spark plug tool, you’ll receive a handful of options. Some will call them ‘upgrades’, as higher-grade materials last longer than cheaper traditional options.
However, depending on what your car needs, that’s not always the case.
For expert recommendations for your car, our Fixter mechanics are always at hand to offer professional advice. We’ve already covered most of the questions drivers ask on our spark plug blog, from the typical costs of parts and replacements to when they might be malfunctioning and when you need to change them.
We’ll also find you the best prices in your area with our online quote system.
What are the different types of spark plugs?
A spark plug consists of a metal terminal that attaches to ignition leads or a coil pack, a ceramic top part (that continues to run the length of the plug inside the bolt/screw section), and, below that, the threaded metal section that screws into the engine cylinder. This threaded section ends with the central electrode and the side electrode creating the ‘gap’ where the spark happens.
Copper spark plugs
- High conductivity – low price
Copper was the original and most used material for spark plug electrodes for many years. Most plugs feature a central copper electrode, typically plated with a nickel alloy to protect the base material. Copper is a soft, high-conduction material, offering an efficient option that’s cheap to produce yet with a relatively short lifespan.
Platinum spark plugs
- A harder metal offering longer life
These plugs have a platinum centre electrode, and being a harder metal, will last far longer than their copper counterparts. They operate efficiently over a wider temperature range, generate more heat than copper plugs, helping to reduce carbon build-up.
Double platinum spark plugs have a central platinum electrode and a platinum side (or ground) electrode. ‘Double’ plugs operate where two plugs share an ignition coil. Both plugs fire at exactly the same time, but the first fires on the ignition stroke and the second fires on the exhaust stroke. This requires the spark to fire from both electrodes, so the heavier duty material provides the necessary protection for both electrodes.
Iridium spark plugs
- Robust, high-performance, higher-priced spark plugs
Iridium plugs are supposed to be the best plugs you can put in your car. The ‘fine wire’ centre electrode is an incredibly efficient conductor, requiring lower voltages for ignition. However, that’s not always ideal for every engine. They tend to feature more in high-performance engines than your family runabout.
Iridium plugs are also available as ‘double iridium’ plugs with iridium operating as the conductor on both the central and side electrodes.
Which metal conductor do I need in my spark plugs?
Once again, it really depends on your engine. If it’s designed to operate with copper plugs, upgrading to platinum or iridium might suggest longer-lasting plugs, but the heat ranges could be all wrong for your car, leading to poor performance, misfiring, and eventually, much more severe issues with your engine. In other cases, such an upgrade could be ideal for your car and lead to years of more cost-effective motoring.
When it comes to replacing spark plugs, we suggest like-for-like if you haven’t got a mechanic to explain how a recommended upgrade or alternative will work in your car. But with Fixter at your fingertips, you’re never without an expert to give you an extra helping hand.
About Fixter
Fixter is revolutionising the car maintenance industry, one repair at a time. Fixter was founded to make car maintenance as easy as booking a taxi. Digital, transparent and stress-free, with world-class customer service. Since launching in Manchester in 2017, Fixter has expanded to more than 100 towns and cities across the UK and provided thousands of car owners with honest, convenient and affordable car repair services.