How long do car ignitions last?

Replacing Car Ignitions
Most modern cars won't start if the wrong key (or no key) is inserted into the ignition cylinder.
Most modern cars won't start if the wrong key (or no key) is inserted into the ignition cylinder.
© Cervo

In distributorless and COP systems, few, if any, ignition system parts need to be replaced. But when these auto parts do need to be replaced, it can be tricky.

In some cases, car part longevity can work against itself. Houser points out that if the spark plugs are left in for a full 120,000 miles (193,121 kilometers) or so, they can be very difficult to remove. Steel spark plugs can fuse with aluminum cylinder heads as they bond themselves together. When the repair tech tries to remove the plugs, they can break into several pieces. At the very least, this process requires special tools. In the worst case, the cylinder head will need to be replaced.

And while the PCM and its sensors can perform without fail for years, another new technological addition can cause problems. Electronic theft deterrents are being built into the ignition cylinder to keep thieves from stealing cars. A chip inside the cylinder "talks" to a chip in the key. If it can't find that chip, the car won't start. So, what happens if the chip in the key fails? Either the car has to be towed to the dealership or a certified specialist needs to come to the car. In either case, the theft deterrent system needs to be reprogrammed. "You don't want to screw it up," says Houser, "because it can damage the car's computer."

Believe it or not, auto part longevity is about to get even longer. The state of California wants to see an extended warranty on new car ignition systems of 10 years or 150,000 miles (241,402 kilometers). This will mean notching up the quality of the current auto parts, like the crankshaft sensors and the coils. However, Houser thinks the auto manufacturers will have no trouble meeting these new standards.

The reduced need for maintenance and car part replacement means keeping a vehicle for several years is much cheaper than it once was, and with fewer parts being tossed in the garbage, it's better for the environment, too. As Macaulay says, "It's worlds apart from the cars of the '70s."

For more information about ignition systems, auto part longevity and other related topics, follow the links below.

Related HowStuffWorks Articles:


  • "How Car Ignition Systems Work." (Oct. 1, 2009)
  • Draper, Dave. "Electronic Ignition Overview." June 2005. (Oct. 1, 2009)
  • Houser, Jim. Hawthorne Auto Clinic. Personal interview. Conducted on Oct. 8, 2009.
  • Macaulay, Leslie. Portland Community College Automotive Service Technology. Personal interview. Conducted on Oct. 7, 2009.
  • Weissler, Paul. "Replacing Spark Plugs." March 1998. (Oct. 6, 2009)

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