Not a single part, but the proliferation of poorly-made “OEM QUALITY” or knock-off auto parts. Amazon is attractive to wrenchers on a budget because you can often get cheaper parts shipped to you in a couple of days.
Let’s say I’m driving an old but still reliable mid-2000s Corolla. There’s a horrible clunking coming from the front end and the ride has deteriorated, and a quick inspection reveals rusty, leaking struts and the bushings are shot. I check the AutoZone down the street, but they want $270 for a set of DuraLast quick struts. You check Amazon then:
Oh now that’s more like it. You buy the $100-cheaper struts, notice that they don’t seem to fit quite right but oh well, you’ll make them work. You get them installed over the weekend, and all is well.
Until six months later and they’re clunking again.
Now, I know that it isn’t a given that this will happen. And I know that, sometimes, you just HAVE to buy the cheapest parts you can find so you can get to work and back. But I have been burned too many times by buying the cheapest parts I could find, whereas I could have found better parts with just a little digging:
I know that Monroes aren’t the best these days, but that’s the same price as the cheapo Amazon struts. Heck, a set of KYBs for a Corolla on Rock Auto are just over $100.
For certain things, it’s fine to go to Amazon. But for critical vehicle components - brake rotors, suspension bits, internal engine parts, gaskets, anything where replacing the part again would be a royal pain if it fails - just go to the auto parts store or a reputable online store and get the name brand part.
Also, can we take a moment to appreciate this: PURSUE MAKES PERFECTION
Now that was a journey. And also a great lesson for any young and naive kids reading this who might just assume that what they read in an ad has to be true. And while we’re at it, definitely don’t cheap out on window regulators. Ask me how I know.