Why Do Ignition Coils Fail?

[DeArya]

An ignition coil consists of a primary coil, secondary coil, magnetic core, switching transistor, and other auxiliary components. The main reasons for ignition coil failure are as follows: 1. High external ambient temperature: Excessive heat can cause the ignition coil to overheat. You can use a wet cloth to gradually cool it down. 2. Overheating of the car engine: If the coil is installed too close to a heat source or has poor heat dissipation, the overheating issue should be resolved, and the coil should be installed farther away from the engine. 3. Improper ignition coil wiring and excessively high generator voltage regulation: Incorrect wiring on the ignition coil may render the additional resistor ineffective, causing the coil to heat up at low engine speeds. If the regulator voltage is set too high, excessive primary current can lead to increased output voltage and coil overheating. 4. Mismatch between the ignition coil and the engine: When replacing the coil, ensure it is compatible with the vehicle model. 5. Poor-quality coils or internal short circuits causing overheating: During vehicle use, forgetting to turn off the ignition switch while parked can result in prolonged power supply. Loose carbon particles in the distributor may cause continuous sparking, leading to overheating, insulation erosion, or even explosion of the ignition coil.

[Alina]

I remember one time my car was shaking like a massage chair. After checking for a long time at the repair shop, they found out the ignition coil was faulty. These things are actually quite delicate, and the most common issue is aging and cracking of internal wiring. After driving for a long time, when the engine compartment temperature gets high, the coil's insulation layer tends to degrade, causing high-voltage electricity to leak. Engine vibration is also a hidden killer—the constant shaking over time can loosen coil connectors or break internal wiring. Using the wrong spark plugs is the most frustrating issue. If the gap is too large, the ignition coil has to work harder to generate higher voltage, eventually wearing itself out. If you're not careful when washing the car, water can seep into the coil connector and cause corrosion or electrical leakage. Unstable voltage is even worse—if the alternator regulator malfunctions, the fluctuating voltage can directly short-circuit the coil. That's why mechanics recommend regularly checking the entire ignition system, especially for older cars, as this part can suddenly fail.

[ErinRose]

My old car had its ignition coil replaced last year, and the mechanic said it was mainly due to the materials not standing the test of time. The plastic casing, constantly baked by the engine heat over the years, gradually became brittle and cracked. The fine copper wire wound inside the coil is even more fragile, and metal fatigue fractures under high temperatures are quite common. Driving in the rain also requires attention—water vapor splashed up from the chassis can seep into the engine bay, and moisture infiltrating the coil connectors can cause green copper corrosion, degrading conductivity. If you've upgraded your audio system or headlights, the increased load on the alternator causing voltage fluctuations is practically a slow murder for the ignition coil. My neighbor’s car had it worse—using substandard spark plugs caused the ignition coil to overload and burn out completely within three months. I recommend everyone periodically open the engine hood to check for cracks in the coil casing and ensure the connectors are dry.

[RiverRose]

It's quite interesting to think about the failure of an ignition coil. Essentially, it's just a large transformer that can reach temperatures over 100 degrees Celsius during operation. The constant thermal expansion and contraction can cause solder joints to crack. The engine vibration acts like a tiny hammer constantly pounding on it, potentially causing the internal coil frame to shatter. If the spark plugs are worn out from prolonged use, the ignition coil has to work extra hard to increase voltage to jump the spark gap, eventually leading to burnout. Water intrusion in the wiring is also dangerous—last time my car went through water, the coil connector corroded and caused poor contact. But the scariest scenario is sudden voltage spikes; when the alternator malfunctions and voltage suddenly surges, it can instantly break down the coil's insulation. Remember to have the technician measure the ignition coil's resistance during every maintenance check, and replace it immediately if any abnormalities are detected.