A car airbag has a strange life. It spends most of its time in hiding until our lives depend on it. Then it springs into action for a few seconds, fulfills its destiny and passes away.
That's not always the story for the noble airbag, and that's a good thing for car owners. In most cars and trucks, airbags never see the light of day. But do these important safety components stand the test of time? Eventually, most things break down on a car. Are airbags any different? The answer is yes — and no.
In early uses of car airbags, a few automakers called for an inspection or replacement after a number of years. But modern technology has enabled airbags to last the life of the vehicle in which they're installed.
The Early Days of Airbags
Car airbags are part of a vehicle's supplemental restraint system (SRS). They have been around since the 1970s and are now standard equipment on every vehicle. Since airbags were new technology then, a number of automakers erred on the side of caution when estimating their lifespan. The owner's manual on early-1990s Honda and Acura vehicles, for example, recommended a dealer inspection of airbags every 10 years.
"That inspection was simply a visual inspection and a confirmation that the self-diagnostic functions were working properly," says Chris Martin, spokesman for American Honda.
Mercedes-Benz, on the other hand, was a bit more conservative. The automaker installed airbag replacement labels on all vehicles sold in the U.S. through roughly 2002, says Diedra Wylie, a spokesperson for Mercedes-Benz. The labels called for new airbags at the 15-year mark. After 2002, Mercedes research concluded that the airbags it produced after January 1, 1992 would last the life of the vehicle, Wylie says.
"Advances in airbag module technology now ensure the lifelong, functional reliability of the airbags," says Wylie.
In pre-1992 Mercedes vehicles with airbags, the part needs to be replaced after 15 years. The vehicle's owner will have to foot the bill of roughly $2,000.
Does an Airbag Expire?
While some automakers have set time limits on when to replace an airbag, the actual components are extremely durable. The key difference is the type of seal used to house the airbag igniter, also known as the squib.
"Almost all squibs since Day One have used what is called 'glass-to-metal' sealing, which is the best for moisture protection," says Douglas Campbell, who is president of the Automotive Safety Council and has worked in the airbag industry for more than 25 years.
"Some earlier non-North American models may have used 'plastic-to-metal' seals, which would have passed the vehicle life tests, but are considered to be potentially not as robust in extreme testing," Campbell says.
Leo Knowlden, a field performance assessment engineer for General Motors, said that GM has used glass-to-metal seals on all its airbags since the very beginning. A plastic-to-metal seal is more likely to accumulate moisture over the years, Knowlden says. This can lead to corrosion of the electrical pins in the igniter and potentially lead to a less responsive airbag.
As proof of the lifetime durability of GM airbags, Knowlden pointed to a 1992 Insurance Institute for Highway Safety study, where a rusty 1972 Chevrolet Impala was crash-tested and both the driver's airbag and passenger airbag successfully deployed. That Impala was one of the first 1,000 airbag-equipped cars made by GM.
And similarly, "airbags from 1990s vehicles are operating correctly in today's accidents," says Campbell.
The National Highway Traffic Safety Administration (NHTSA) knows of successful deployments of airbags more than 30 years after production, says Jose Ucles, a NHTSA spokesperson.
The Self-Diagnostic Function
The burden of determining whether a car airbag is working properly isn't on the vehicle's owner. Nearly every vehicle equipped with an airbag has a diagnostic function and an SRS indicator light that signals when there is a problem.
"When you start your car, the SRS light comes on a short period and then goes off as the self-diagnostic is completed by the computer," says Martin. "If the light either never comes up [at start-up] or comes on and stays on, then it can indicate a problem with the system."
In GM cars, the self-diagnostic function checks the system 10 times a second, says Brian Everest, GM's senior consultant for major accident reconstruction.
The Modern Airbag Era
Knowlden defines the modern era of airbags as the period starting in the late 1980s, when federal legislation was proposed to make airbags mandatory. Dual airbags were required on all new cars beginning with the 1998 model year. Light trucks followed a year later.
Edmunds contacted Ford, General Motors, Honda, Mercedes-Benz and Volvo for this article and all confirmed that their current airbags will last the life of the vehicle. Replacement labels and recommended dealer inspections are largely a thing of the past, carmakers say.
"Now that we have many years of experience with the self-diagnostic systems, the dealer inspection is not really necessary," Martin says.
Airbag Tips for Consumers
Trust the Automakers
In the early years of airbags, their reliability was based upon lab simulations, and carmakers cautioned owners accordingly. But now vehicle manufacturers are more confident, Campbell says. They have produced millions of airbags and have more than 25 years of real-world experience.
