Are aftermarket replacement parts dangerous?

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Ever had a friend or relative who sold a car after it had serious structural repairs because they didn’t feel safe in it? Turns out they may have been on to something.

Mechanics, especially those with ties to insurance companies that typically foot collision-repair bills, often use aftermarket replacement parts because they are significantly less expensive than original equipment manufacturer, or OEM, parts.

Ford recently published an engineering study that compared these non-OEM parts with the original parts installed on 2004 to 2007 F-150s and 2005 to 2009 Mustangs.

The study found that non-OEM replacement parts were often made of flimsier materials like molded plastic, and could cause a car’s safety equipment to malfunction in an accident. The engineers singled out air bag sensors in particular as a potential source of trouble. Airbag sensors are often designed to detect vibrations in the material they’re mounted on to calculate the best time to deploy. The study found that differences in materials could cause a car’s safety systems to miscalculate when the airbags should fire to best protect passengers.

Of course, it might be wise to take the study with a grain of salt, being that it’s an analysis of products that compete with OEM parts Ford sells. But it’s also not hard to imagine auto insurance companies jumping on the chance to save big money on a repair job without necessarily making sure new car could pass the kind of collision tests new cars are subjected to.

It also underscores the need for people who’ve been in a car accident to be aggressive advocates for themselves when dealing with repairs paid for by auto insurance companies.

What do you think? Have you ever felt uncomfortable with how an insurance company handled a repair? Should insurance companies be required to pay for OEM parts?