Safety, performance, aesthetics, noise, comfort, reliability, and durability are the goals that keep automotive engineers up at night, and the miracle solution has, so far, been “more plastic.” Manufacturers constantly feel pressure to reduce weight and cost for a variety of regulatory and consumer preference reasons, and plastic is lighter and cheaper than metal. So in it goes! Never mind that plastic refuses to break down in the environment, leaving us with microplastics in our bodies, or that plastic engine parts will be nearly impossible to repair in the future, meaning some awesome current cars could be unpreservable. Keep shoveling plastic in there.
Take plastic engine covers (please!). Automakers love these things. Complex electronics thousands of times more powerful than what we used to go to the moon must be shielded from moisture, and plastic is impermeable. Engines are noisy, and your average Joe doesn’t want to hear a Kia inline-4 whine up to 60 mph, so a plastic cover helps reduce the thrum. Sure, engine covers are getting so large that once you close the hood, it’s like putting a hat on a hat, but how many people want to gawk at a Mazda CX-90’s powertrain anyway? Well, Mazda, if you made the engine as pretty as the Miata’s, maybe people would.
The ugly truth is, plastic solves a lot of automotive problems, at least in the eyes of automakers. Even air intakes seem to benefit from being plastic thanks to their smooth interiors, which reduce drag on incoming air compared to aluminum intakes. Heck, oil pans are often made from composites now, and they’re way lighter than metal ones. So, thanks to plastic, we can actually have better-performing, more reliable, quieter cars? Perfect! As long as we ignore the future, this is great news!
Plastic crumbles forever
The first issue with plastic is that it’s a lit fuse on a stick of dynamite, whether from an environmental standpoint or a preservation/repair standpoint. Durability has long been an issue for old automobile plastic, and despite strides to make more durable and stiffer plastic, it will still crumble eventually. You can make the fuse for the dynamite longer, but you can’t snuff it out.
As for the preservation of plastic parts, well, sorry. While steel lasts a long time and can be quickly recycled, such is not the case for plastic. It will eventually weaken and either become brittle or sticky. And so much stuff causes plastic to degrade, from heat and sunlight to exposure to a cornucopia of solvents and chemicals. You can put your car in sealed storage, but the plasticizers that keep plastic looking, feeling, and acting new will evaporate, and it will still degrade.
Oh, then there are the microplastics. Microplastics may be just the worst for the health of every living thing. When a plastic car part inevitably ends up in the crusher, Science of the Total Environment reports, it releases a bunch of microplastics. This will be especially fun as companies try to make even load-bearing parts, such as plastic suspension springs, a reality. But, hey! Fuel efficiency goals met for the next few years, so pass the party favors! And this is the ugliest truth: the real problems are far enough away that manufacturers don’t have to care. What does it matter if your car’s plastic parts fall apart in 30 years? They stopped making parts for that car eight to 10 years after it left production anyway.
Plastic protects your engine, but at what cost?
Yes, plastic covers protect your engine from corrosive dust, reduce noise, and protect wiring and other components. If you remove the plastic sarcophagus that envelops your car’s engine, underneath you’ll likely find tons of wires and a tiny engine that looks like a miniature dystopian factory. Or, depending on the car, ripping off that cover might remove the built-in air filter, too. Plastic is so integrated into your vehicle, especially the engine bay, that there’s no going back. It’s an addiction, and there’s no gum or patch for it. And the car-buying public isn’t exactly making it easy to quit plastic, even though it can make plenty of parts really hard to service.
Buyers want more features, better fuel economy, and more reliability. They also want to pay less. That’s why plastic’s insidious infiltration has turned the underside of your car’s hood into a petroleum product playground. Carmakers put so dang much plastic in the engine bay because it’s a cheap, easy way to accomplish goals buyers want. Plastic makes cars more durable and reliable. Right up until they aren’t, and become an environmental and repair disaster.