Your car’s ignition coils provide the high-voltage electrical current that allows your spark plug to generate its spark. These parts are humble in appearance and use relatively simple electromagnetic principles. An ignition coil has two windings, the first uses 150 to 300 turns of wire, and the second increases this value by about 100 times (15,000 to 30,000 turns). The resulting electromagnetic field takes a typical 12 volt electrical current and amplifies it to about 20,000 volts like a transformer.
The humble coil of wires is a critical component in properly running motors. Together with sensors that detect the position of the crankshaft, the coil provides a precisely timed supply of electrical current to keep the engine moving. But over time, these sensors can fail, and the ignition coils themselves can go bad. This may be the result of moisture issues, or just normal wear and tear.
A coil that is bad will usually result in a check engine light, and if you allow the problem to persist, you will likely experience a rough idle, weak acceleration, and engine misfiring. These additional stressors can spiral into other components under the hood, making the problem much worse than simply replacing a part. In fact, replacing the ignition coil is something you can do yourself.
How to change the coils
Changing the ignition coils in your car is a fairly simple process. It’s something even a beginning car enthusiast can do, so it’s a great starter project for someone looking to become more DIY-savvy when it comes to maintaining their vehicle.
The first thing you’ll need to do when preparing for an ignition coil replacement revolves around your work space. You don’t want to work on a hot engine, so wait until the car cools down (or tackle the replacement before driving the vehicle for the day). To change the coil:
- First, lift the parking brake to make sure the car does not move during installation, and disconnect the negative battery terminal.
- Disconnect the existing ignition coil; you can find this by following the wire in the center of the distributor cap or by locating the spark plugs.
- If necessary, remove any plastic covers or tubes that rest on the ignition coil.
- Once you’ve found, accessed, and disconnected the coil, remove the bolt holding the component in place.
- Start moving the ignition coil. The part may come off or require a twist to remove, depending on the particular car model.
- Compare the new coil to the old one to make sure the new part will provide the required function, then apply dielectric grease to the inside of the coil. If you also need to change the spark plugs, this is when you should tackle replacement.
- Slide the new bobbin into its slot and push or turn it until it clicks into place. Then replace the retaining bolt.
- Connect the electrical connection of the coil and then replace the overlapping parts and reconnect the battery cable to the terminal.
how much i could save you
Changing ignition coils yourself can save you a significant amount of time and money. For one, a single coil can cost as little as $35. However, you may need to replace multiple ignition coils, or your car may use a more expensive part (up to $300 in extreme cases). If you only need a simple component, the change may take just a few minutes and cost a few dollars.
Even for a beginner, fiddling with components and rewiring with this new part installed requires basic dexterity and just a smattering of common sense. Plus, by taking safety precautions before beginning the replacement process (unplugging the battery and setting the parking brake), the task requires few significant safety risks—you won’t have to crawl under it or get your hands dirty.
Alternatively, taking your vehicle to a dealership or mechanic to replace this component will cost you time and an additional approximately $75 to $130 for the billed hour a mechanic will spend with your car (the going rate per hour in the US). You may also be exposed to a surcharge for the part itself, further raising your total expense. Learning to identify the telltale signs of an ignition coil starting to fail can help you save money that can and should go elsewhere in your budget.
