Too much plastic on todays vehicles.
In fact today's vehicles contain an average of 428 pounds (about 194 kg) of plastics and polymer composites, accounting for 50% of a vehicle's volume, yes 50%!
The drawback to this that many of us mechanics are seeing include:
High component failures: Intense heat cycling causes critical plastic components such as thermostat housings, coolant fittings, oil filter housings, and timing guides to become brittle, crack, and leak over a short time.
Easily breakable components: Components made so fragile it is often impossible to remove without them breaking. As an automotive technician sometimes I feel like I am working on a cheap kids toy instead of a car!
Unserviceable Assemblies: Instead of typically replacing a small, inexpensive gasket or component, mechanics are often forced to replace an entire expensive plastic assembly.
Fragile Exterior Parts: Touchpoints like door handles and latches molded from plastic leading to sudden breakages when pulled with force.
Critical Engine Failures: Automakers use plastic for high heat components like intake manifolds, oil pans, coolant housings, and thermostat assemblies that often leak or crack. Age and heat are a big enemy of plastic.
Recycling Issues: Only a small fraction of the plastic in new vehicles comes from recycled sources, and most end-of-life vehicle plastics end up in landfills. Not good for the planet and microplastics are very bad for humans.