Auto manufacturers recommend changing your spark plugs as a part of regular car maintenance, typically every 100,000 miles. Having working spark plugs is vital to keeping your engine running, as they continuously ignite the air-fuel mixture in your car's cylinders.
That being said, it's important to change them when it's recommended by the car's manufacturer, or sooner if you notice any signs that it might be time.
Signs it's Time to Replace Your Spark Plugs
Here are some of the telltale signs that it may time to clean or replace them. If they aren't maintained properly, some serious damage to your engine could result.
- Trouble starting. If the battery is fine and the gas tank isn't empty, another potential reason is faulty spark plugs.
- Multiple cylinder misfires. When the engine stops and starts, it's a possible sign that some of the cylinders aren't firing properly. This can also increase emissions.
- Rough idling. When the stationary idle becomes bumpy and loud, it's a likely sign that the spark plugs aren't in good shape.
- Poor fuel economy. Bad spark plugs can lead to incomplete combustion, increasing the rate at which your vehicle burns fuel.
- Sluggish acceleration. If your car is having trouble speeding up, it may be due to faulty spark plugs decreasing the efficiency of continuous ignition.
Before You Get to Work...
If you're handy with a ratchet and are confident with what's under the hood, you can probably replace your spark plugs on your own. Be sure to let the engine cool completely before you begin.
If your vehicle has spark plug wires, most owner's manuals recommend that the wires be replaced at the same time as the spark plugs, so you'll probably want to have both new plugs (the correct ones for your vehicle) and new wires on hand before you start the job. (Note: Instead of wires, some newer cars have coil on plug, or COP, assemblies.) You'll also need a spark plug gap gauge, anti-seize lubricant, and a 3/8 inch ratchet.
If you aren't replacing the wires, make sure you change one spark plug at a time so you can be sure you connect the right plug to the right wire. If you are replacing the wires, look through your vehicle repair guide for a wiring diagram. Each must be connected to the distributor cap and to the cylinder head in order. The vehicle repair guide will be essential in determining the correct socket size, spark plug gap, and tightness during installation, as well.
Guide to Replacing Spark Plugs and Wires
- First, remove the spark plug wire gently by the wire boot. (If your car has coil on plug assembly instead of wires, remove the COP by the boot.)
- Wearing eye protection, clean the area with compressed air to get dirt and grit away from the plugs. This will help ensure that nothing falls into the cylinder heads while they are open.
- Unscrew the plugs using your ratchet. As you remove each plug, inspect them for signs of problems.
- Use your spark plug gap gauge to match your new plugs with the specified gap listed in your vehicle repair guide. Insert the gauge between the inner and outer electrodes, and bend the outer electrode (the hook) backward or forwards to meet your vehicle's specs. Make sure you match the exact gap size to maximize the efficiency of your engine.
- If your vehicle's cylinder heads are aluminum, make sure to use anti-seize lubricant on the new spark plugs to ensure that no reaction occurs between the metals.
- Use your ratchet to attach the new spark plugs and tighten them until they are secure.
- Reattach the wires, twisting them to get the boot into the right position above the plug. They should connect with a click. Once you've replaced all of the plugs, you're done!
If you prefer not to replace your spark plugs yourself, be sure to give us a call at All in the Wrist Auto Repair. We'll give your vehicle top-notch service so that you can get back on the road safely.