How To Clean Coil Packs

Coiled, metal tubes inside the engine called coil-packs are a common problem in older cars. When they fail, it can lead to a no-start scenario, where the car won’t even turn over. It’s usually not a single coil failing; it’s usually all of them! Thankfully, replacing Coil Pack is an EASY job with just a few tools and about an hour of time. In this article we will learn more about the reasons why these coils fail and how to troubleshoot this type of failure. The most important thing you should know about Coil Packs before reading any further is:Replacing them requires some DIY knowledge…but not much. Even if you’re still learning, you can do this! Here are some things you should keep in mind before diving into this repair:

What is a Coil Pack?

The Coil Pack is a group of spark plugs that are connected to a module that controls the spark. The Coil Pack acts as an electrical switch. When the engine is running, the module sends a signal to the coils inside the coil pack. This tells it to generate an arc that jumps between the two electrodes. This spark ignites the gas in the cylinder, which drives the pistons, which turns the crankshaft. A typical coil pack is a group of spark plug wires attached to a black box. The box contains an electronic circuit board that manages the spark for each of the spark plugs in the coil pack. The spark plug wires are attached to the black box.

Why Do Coil Packs Fail?

Coil packs have a tendency to fail at low miles due to age, overheating, and contamination. The biggest reasons for coil pack failure are:

  • Poorly maintained engines are more likely to have excessive carbon buildup on the inside of the engine. This buildup can reduce the lifespan of the coil packs.
  • The engine is contaminated with water or other substances that cause the coil pack to fail prematurely.
  • The engine is overheated. This can cause the metal of the coil packs to expand, putting undue stress on the electrical contacts inside the coil packs. If you’re experiencing issues with a car that has recently been repainted, it may be due to a poor paint job. Low-quality paint can oxidize and cause electrical issues with the coil packs.

How To Clean Coil Packs

Coil packs are an important part of your car’s ignition system. They provide the spark that ignites the air/fuel mixture in the cylinders. Over time, coil packs can become dirty and need to be cleaned.

There are a few ways to clean coil packs. One way is to use a can of compressed air. Another way is to use a soft brush.

  • Start by disconnecting the negative terminal of your car’s battery. This will prevent any sparks from happening while you’re working.
  • Next, remove the coil packs from the engine. You may need to consult your car’s manual to find out how to do this.
  • Once the coil packs are removed, you can start cleaning them. If you’re using compressed air, hold the can about 6 inches away from the coils and spray in short bursts. If you’re using a brush, gently scrub the coils.
  • Be sure to clean all the nooks and crannies, as dirt can build up in these areas and cause problems.
  • Once you’re finished cleaning, reinstall the coil packs and reconnect the negative terminal of the battery.

When Should You Replace Coil Packs?

If you have spark but the engine isn’t running properly, it may be time to replace the coil packs. If you have spark and the engine isn’t running properly, then you may have a vacuum leak or fuel problem that isn’t related to the ignition system. If you lose spark, then you may have a bad ignition module, a bad spark plug, or a bad coil pack. If you have spark but aren’t getting fuel, then you’ll need to check the fuel system. If you have spark and the engine is running but you’re having issues with the way the engine is sounding, then you may have an issue with the engine timing. Timing can be thrown off if the engine is dirty, the engine is low on oil, a belt is loose, or a drive belt has come off. You can diagnose these issues by visually inspecting the engine and looking for contaminants that may be holding the engine back.

How to Test for Coils Dying?

You can use a voltmeter to test the voltage across the plugs. When the plugs are supposed to fire, you should see about 12-16 volts. If you’re getting less than 12 volts, then it means that the coil isn’t providing enough power to jump the plug gap. This can indicate that the coil pack needs to be replaced.

You can also use a resistance tester to see if the plug has continuity. If the plug has low resistance, then it means that the plug is good and the issue is somewhere else in the circuit. If the plug has high resistance, then it means that the plug is bad and needs to be replaced.

How to Replace Coil Packs?

There are a few methods that can help you change the coil packs in your car. You can:

  • Disconnect the battery, remove the spark plugs, and then unbolt the old coil packs.
  • Remove the intake manifold and unbolt the old coil packs.
  • Remove the old coil packs while the engine is still in the car. You can do this by unbolting the engine mounts or removing the spark plug wires from the module.
  • You can also unbolt the old coil packs while the engine is still in the car and then disconnect the spark plug wires from the module. Some people prefer this method because it provides access to the module for testing.


The coil pack is a common ignition system component that can fail on many different types of vehicles. It is important to know the signs of a failing coil pack, and how to test for it. If you suspect that a coil pack is failing, it should be replaced as soon as possible. This will prevent the issue from becoming more serious and causing more damage to the engine.

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