Ignition coils are rugged and reliable components of your car’s ignition system. They are durable and generally last for 100,000 miles or more.

However, they can deteriorate faster due to imperfect driving and engine conditions and may need to be replaced earlier than their prescribed lifespan.

The following are the key factors that cause overheating and damages ignition coils:


Overheating is the most common reason for damaged ignition coils. Most ignition coils are made of a silicon-iron alloy that has a threshold to heat. Due to wear and tear and imperfect running conditions, the ignition coil can heat excessively.

This can damage the ignition coil and you will need to replace them earlier than their lifespan.

Electrical Surges

Ignition coils are designed to carry large amounts of energy.

They are generally very reliable but the large amounts of energy running through them may impact them over time. It leads to wear and tear of the insulation between coil windings, coil towers, or coil housing. When the insulation degrades, it can lead to overheating of the ignition coil that leads to its damage gradually.

Resistance Issues

The resistance levels in an ignition coil should be maintained at a constant level for its proper functioning. Changes in the resistance level impact the functioning of the ignition coil. If the resistance is lower than required, it can cause more electricity to flow through the coil windings.

This can damage the entire ignition module. If the resistance is too high, then it will not provide enough power flow through the windings. This will provide a weak spark and lead to failure of the ignition coil and other related spare parts.


Moisture is another common factor that damages the ignition coil.

Oil leaks are the most likely source of moisture that can damage the ignition coil. In most modern cars, the ignition coil and spark plugs are mounted into a tube in the valve cover. With overheating, the seal between this tube and valve cover can break.

This causes engine oil to leak inside and fill up around the ignition coil, thereby damaging it. You should regularly check the ignition coil for any oil leaks for preventing further damage to it and other important car parts.

Moisture can also result due to condensation. If not checked, the car’s AC condensation can build up and drip directly into the ignition coil which can damage it.

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