The Bright Spark’s Guide to Plug Repair

Spark Plug Repair

In every petrol engine, the role of the spark plug should never be downplayed. Tasked with the job of igniting the fuel and air mixture in the engine, without them, your motor wouldn’t be capable of starting, let alone running.

Tell-tale signs that your spark plugs aren’t operating as they should include problems starting your engine, higher than usual fuel consumption and a misfiring engine. If these issues sound familiar, you might want to consider swapping your old plugs for a brand new set.

Luckily, making the move from old to new plugs isn’t a major job – both in terms of time and expense. To get the job done, you’ll need:

1. A ratchet

2. Ratchet extension bar

3. Spark plug socket

Locating your spark plugs

Before you go climbing all over your engine, check your car’s manual to find out exactly where your spark plugs are located.

In the majority of four and six cylinder engines, the spark plugs will be located on top of the engine, underneath a protective cover, whereas in V6 or V8 models, they’ll be split 50/50 on each side of the engine body.

Removing old spark plugs

Once you’ve located your spark plugs, you’ll notice a series of plastic covers – commonly known as wire plugs – are placed over the top of them. To remove these, simply grip them at the base and pull upwards. Just remember to allow your engine to cool first.

Next, attach the spark plug socket to your extension bar before placing it over the spark plug. From here, undo each spark plug using the ratchet – although you might find that once they’re loose, it’s easier to remove them using just the bar and socket.

Mind the gap

Once you’ve removed each spark plug, you’ll notice that on the underside of each one there will be a piece of metal that sits away from the main body of the plug. The distance between this piece of metal and the plug is known as the spark gap – a gap that can be measured using a spark plug gap measuring tool.

To avoid unnecessary damage or increased fuel consumption, when buying new plugs it’s important to make sure the spark gap on your new set matches those recommended in your vehicle manual.

Fitting new spark plugs

Once you’ve found a set of plugs to fit your vehicle, start by gently screwing each spark plug back into the engine. Don’t use the ratchet straight away – instead, start by using the socket and bar. Doing this will help to ensure you line up the threads of each plug properly, rather than cross-threading each fitting and damaging your engine.

Although you’re fitting new plugs, it’s important to remember that after 30,000 miles these too could need replacing, so be sure to lubricate them with some anti-seize fluid before securing them with your ratchet.

To find the perfect set of plugs for your car, simply enter your registration number on our homepage and let our search tool do all the hard work for you!