How Long Do Coil Packs Last?

The modern ignition coil has gone through many changes over the years. Changing from a distributor type ignition system to today’s coil on plug style in modern cars has increased the performance of the ignition system. It also reduced the amount of moving parts in the ignition system. This has decreased the amount of maintenance needed for the ignition system and parts that need replacement and really changed the answer to how long do coil packs last. 

An ignition coil pack is a very important part of a vehicle’s ignition system operation. The main purpose of the ignition coil is to increase the voltage supplied by the battery of a car to create a spark. The 12 volts supplied from the battery is increased to between 12,000 to 20,000 volts or more to jump the spark plug gap. When the spark jumps the gap it ignites the air fuel mixture in the cylinder and begins the combustion process.

voltage jumping a gap and text reading " 12,000-20,000 volts needed to jump the gap

However, just like everything on a vehicle, they will eventually fail. 

So how long do coil packs last? Let’s find out. 

Why Do Coil Packs Fail

Ignition coil packs generally last the lifetime of the vehicle if it is maintained correctly. Or, at minimum many years before they require replacement. If the ignition coils do start to fail, they will start to fail between 5 and 7 years or roughly between 120,000 to 150,000 miles. 

There are many things that cause an ignition coil pack to fail earlier than expected. This is generally due to where the ignition coil packs are located in the engine bay of the vehicle. Let’s take a look and see what are some of the things that will cause a coil pack to have a shortened life.

Heat

Every engine component is subjected to large amounts of heat in the engine bay. Once the hood is closed and the engine warms up there is lots of heat built up inside. 

Some components are cooled with the cooling system of the vehicle but the ignition system is not. If the vehicle overheats or is exposed to excessively high temperatures under the hood it can cause the ignition coil packs to fail earlier than expected. 

Vibration 

All electrical components do not do well with vibration. As you can imagine if you spent all day shaking the daylights out of your computer it probably would not have a long life either. 

The engine is full of vibrations when it is running. There is no way to limit the amount of vibrations that the ignition coil is exposed to. 

Age 

The age of the ignition coil has a lot to do with when it fails. The internal electronics can start to fail or even the outside plastic insulation can crack due to age. This allows moisture to enter the ignition coil which will cause it to fail prematurely. 

Spark Plug Condition

old worn out spark plugs that need replaced

This is one of the largest reasons your ignition coils fail early. When your spark plugs wear the gap of the spark plug increases and carbon accumulation can form on the electrode.

This causes the voltage that is required to jump the gap in the cylinder to increase. When the voltage required increases the ignition coil has to work very hard to do its job correctly. This causes the ignition coil to wear out prematurely.

So make sure that you are tuning up your vehicle on a regular basis. Tuning up your vehicle will see you replacing the spark plugs to ensure that the spark plug gap does not get too wide. By doing this you will extend the lifespan of your ignition coil packs.

Spark Plug Wires

Just like spark plugs a faulty spark plug wire can have the same effect. A bad plug wire can cause the voltage to increase and require the coil packs to have an increased voltage output.

This reduces the lifespan of the coil pack.

A close up of an engine with a distributor type ignition system

Quality

When replacing the ignition coil packs in your vehicle make sure that you are using the highest quality part you can afford. 

Cheap coil packs skimp in all areas so  they can give you a low purchase price. Because of this the electronics or possibly even the ignition coil body can fall apart early causing it to fail. 

Replace With Name Brand Coil Packs

Stick to name brand manufacturers. It can be tempting to get a coil pack from a place online for $20 but you may end up having to replace it often due to the bad quality that may be present. 

How Do You Know If You Have A Bad Coil Pack

There are many different things that you may notice when you have a bad coil pack. Your check engine light could be illuminated, your vehicle could be shaking or vibrating when you are driving, and your fuel economy will decrease a lot.

When Should You Replace An Ignition Coil

Ignition coils are a part of the vehicle that is not regularly replaced as part of maintenance. It is true that some vehicles are known to have bad ignition coils that fail early. Mostly due to the location of the coils or some other underlying issue. These vehicles will tend to need coils replaced earlier than usual, but this is an unusual case. 

You only need to replace the ignition coil if you or your mechanic have decided that you have a bad ignition coil. 

You Do Not Need To Replace Ignition Coils When You Replace Spark Plugs

a pro tip, you do not need to replace all the ignition coil packs at the same time

An ignition coil should never need to be replaced as a regular maintenance item. There are many mechanics that suggest you replace all of the ignition coils when replacing your spark plugs. 

This is unnecessary and can cause the bill to increase significantly. Having to replace all the coils on a V-8 engine for example can add over $400 to the repair price. Save the money and only replace the faulty coil when replacement is required.

Summing It Up

As you can see a bad ignition coil is one of those parts of cars that you replace only when it is broken. There are many factors that determine how long do coil packs last. Depending on the vehicle, replacing ignition coils and installing new spark plugs can be an excellent do-it-yourself repair for car owners of all skill levels.

John Morris
John Morrishttps://autoknowit.com
John Morris is the technical editor for AutoKnowIt.com. His years of experience in automotive repair as well as an automotive professor have prepared him to ensure that even the most technical information is accurate and concise at all times.

Latest Articles