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A Quick and Easy Guide for Changing Your Spark Plugs

A Quick and Easy Guide for Changing Your Spark Plugs

The most typical reason for removing spark plugs is to replace them with new ones. But first, you might want to check what condition they are in before changing them, or you might need to test for spark to make sure it is not an ignition issue. Do not fear. The process of changing your own spark plugs is not as overwhelming as it sounds. It is a task that can be pulled off by a skilled DIYer. 


Learn how to change spark plugs yourself and save a big amount of money on car maintenance costs. It is a simple task that will take you about an hour to do. Read on to find out how. But first  learn the basics about spark plugs: its function, its importance and when to know when it is time to replace them.

 

Why it is important to change your spark plugs periodically

Spark plugs do an important job in delivering a car’s power, performance, fuel economy and dependability. They are one of the hardest working parts of your car. But despite its vital role in a vehicle’s overall performance it is often taken for granted. 

Spark plugs should be replaced periodically because worn out or damaged spark plugs cause poor performance such as sluggish acceleration, hard starting and misfiring. It is a pity many car owners are making a mistake of delaying spark plug repair on their cars, even after they have failed. 

 

What happens to a spark plug as it gets old

Spark plugs can last long but sooner or later as they age you need to replace them. Through the years and the thousands of miles a vehicle travels, you can expect deposits form on your spark plugs. The buildup caused by the interaction of the air-fuel mixture can cause pre-ignition of the fuel. An aging spark plug becomes unreliable in supplying energy for your vehicle. Another event that happens when a spark plug gets old is its gap expands making it harder to jump. The correct or specific gap is important to achieve the right level of combustion at the right moment. As the spark plug gets old, its gap widens due to normal wear and tear, extreme temperatures and debris. When the gap becomes too far apart, combustion will be ineffective. 

When to inspect and replace spark plugs 

You do not have to change your spark plugs very often. In fact, it takes years and many miles before you would need to have them replaced. Most vehicle manufacturers recommend changing your spark plugs at 30,000-mile intervals. But the life of your spark plug would still depend on its type and the condition it is in. For instance, copper plugs have the shortest life, but there are plugs that can last four times longer than copper ones. What you have to do is to follow the spark plug service intervals as indicated in your owner’s manual to determine when to install new spark plugs. However, if you can no longer remember when was the last time you changed your spark plugs, you would have to pull them and check the condition and their gap. If you already went into trouble checking your spark plugs, you might as well replace them and begin a new baseline for the future. 

Keep in mind that guidelines set by manufacturers for how often to install new spark plugs tend to be excessively optimistic for its own good. For instance, if you’re already at the 80,000 mile-mark on a set of 100,000 mile-plugs, it already means they are 80 percent worn and are now starting to affect the engine’s performance and gas mileage negatively. The worn out spark plugs can also seize in the cylinder head. The removal of a seized plug can be expensive, especially if the cylinder head’s threads are damaged. Early replacement becomes the better option when gas mileage is starting to go down and to avoid possibility of seized plugs. 

 

Should you do it yourself or Make a Pro Do it?

Well, the answer would depend on how comfortable you are in doing it, and on the type of engine your vehicle has. Some V-6 models require the removal of certain portions of the intake manifold to install new spark plugs. If you are not confident in doing that, then it is better to let a pro do it. On the other hand, if your engine allows you easy access to the rearbank, then DIY is definitely a good option. Just make sure you gap the spark plugs the right way and use a torque wrench.

Make sure you have all tools needed. You can get these tools at auto parts shops and online suppliers. Do not forget to ask the shop clerk for the spark plug gap and specifications. Also buy a small packet of dielectric grease. If you are taking it to a pro, make sure to ask how much spark plug replacement cost before scheduling an appointment. 

 

STEPS IN CHANGING YOUR SPARK PLUGS

Take note of the tools you would need: torque wrench, gap gauge, needle-nose plier, swivel socket, rags, spark plug wire puller and socket/ratchet set. Also make sure you have the materials needed: spark plugs (of course!) and anti-seize compound. 

Now that you have all the tools and materials needed let’s begin:

    1. Find your spark plugs. In most modern vehicles, the spark plugs are placed near the top of the engine. Take note that they might be hidden by a plastic cover or buried under a pile of wires.

 

  • Remove the plastic “vanity” cover (if there’s any) and the air cleaner assembly from the top of your vehicle’s engine. Clean your work area. 

 

  • To make sure you restore the vacuum hoses you’d remove to the right place, have them labeled. 
  • Get rid of miscellaneous debris surrounding the ignition coils to make sure crud won’t fall into the cylinders by blasting compressed air. Then blow away any remaining dirt off the engine prior to setting out your tools and new plugs.
  1. Remove the ignition coil and/or boot. To do this you must disconnect the ignition coil electrical connector by pulling up (or depressing on) the locking tab. Take the connector off the coil. Pull out the coil hold-down bolt then remove the entire coil and boot assembly. 
  2. Unscrew the old plugs. Remove dirt and grime on the old plug. Slide the right size spark plug socket over the plug. It is recommended you use a swivel head spark plug socket since it will make the job a lot easier. You will most likely need an extension of certain length so you could reach the plug. Loosen the plug by rotating counter-clockwise. Take note though not all engines have accessible plugs. It is harder to get to the plugs on compact engine compartments but all plugs can be removed. 
  3. Gap all plugs before installing them. Use the feeler gauge to make sure you gap the new plug correctly before installation. The space between the two electrodes is the gap specification being referred to. It varies from one car to another but it typically falls between .02 to .06 inches range. If you want to save yourself from a big amount of hassle, then make sure to get the correct gap the first time. You can ask a local auto parts shop, a dealer or Google for the right measurement if you are not 100 percent sure about it. Precision is key. Here are the specific steps:
  • Slide the correct gap gauge between the electrodes. 
  • When the gap is too small, you can open it using the gap gauge by prying up.
  • When the gap is too wide, you can tap the side electrode slightly on a wooden or any solid surface.
  • Put a small amount of anti-seize compound on the plug threads and hand thread the plug into the cylinder head.

Tip: Invest in proper tools and equipment (such as a fine gap checker or a feeler gauge which is more precise) if you’re planning to start changing your own spark plugs. 

  1. Install the new spark plug – Using a torque wrench and the manufacturer’s spark plug torque specifications is a must especially with today’s car engines. Insufficient torque can cause a plug to blow out of the cylinder head, taking threads with it. On the other hand, if the torque is too much it can distort the plug. When using an anti-seize compound on the plug threads, decrease torque by 10 percent. In case you do not have a torque wrench then check the spark plug manufacturer’s website to know manual tightening techniques and spark plug torque specifications. 

Tip: Always check your new spark plug for damage. If you accidentally dropped it, inspect for cracks in the porcelain. The side electrode should be straight and should line up with the center electrode. If not, you can reposition it using a needlenose pliers. Do it gently. 

  1. Lube, reinstall and fire up. Lubricate the inside of the spark plug boot with a thin coating of dielectric grease before reinstalling the coil. The grease will make it easier for you to remove the boot in the future and will prevent misfires from happening. Pop the ignition coil back into place, reinstall the coil electrical connector, the hold-down bolt, the air cleaner and the vanity cleaner. Basically put back any part you had to take off to get into the plugs and you’re all done. All you have to do now is to start your engine to check if everything works the way it should. 

BENEFITS OF CHANGING A SPARK PLUG

Congratulations! You have successfully replaced a spark plug on your own. Aside from gaining a new skill, the main benefit of having a newly installed spark plug is knowing your car will start without a problem. But other than the obvious, here are more benefits of installing new spark plugs:

  1. Fully functioning combustion system. When your spark plugs are fully functioning you get to enjoy consistent production of optimal combustion. Say goodbye to performance issues you used to have.
  2. Save money on gas with improved fuel economy. According to the National Institute  for Automotive Service Excellence, misfiring spark plugs can reduce fuel economy by 30 percent. Installing new plugs at the right intervals maximizes fuel efficiency.
  3. Smooth and active starts. You would definitely notice the difference of a new spark plug the first time you turn on the ignition. No more jerky starts.
  4. Less harmful emissions. You are also doing Mother Nature a favor. The Environment Protect Agency states that regular engine tune-ups particularly changing spark plugs periodically do not only save gas but also help in reducing air pollution. 

SYMPTOMS INDICATING YOUR SPARK PLUG NEEDS REPLACEMENT

Just like any other parts of your vehicle, you can hear, feel and sense spark plugs that are failing. Here are common signs your spark plugs are telling you that they are retiring:

  1. Pinging or rattling sounds. When spark plugs start misfiring you may notice unusual noises. This is coming from the force of the pistons and combustion not functioning properly. Pistols move at high velocities. When the spark plug fires at the wrong time it can cause constant rattling or knocking noises.
  2. Poor performance. Spark plugs play a crucial role when you accelerate and change gears. If your spark plug is not working properly, your vehicle performance will suffer. You will experience a sluggish drive. Not to mention you are wasting fuel.
  3. Reduced fuel economy. Fuel is wasted because your car fails to receive the right amount of heat-generating spark at the right time.
  4. Trouble starting. If your car is having a hard start or feels disjointed and jerky when you start the engine, your spark plugs may not be functioning right. This results in misfires and erratic performance.

If you’ve experienced any of these symptoms in your vehicle, it is best to have your vehicle checked in order to prevent further problems. You can do the inspection on your own or you can go to a mechanic. Healthy spark plugs are important to your vehicle’s ability to start up and remain powered.