Plastic Parts

By Brandon Baldwin

Have you looked under the hood and under the car nowadays?  There is more plastic the newer the car!  Plastic is now used for parts we wouldn’t have thought of using plastic for just 20 years ago, but then, what did we use before plastic?  

The  first  cars  had  wood, steel, and iron.  Eventually, aluminum  came  along  to  make  parts lighter.  Speaking of lighter, remember fiberglass body panels?  Great stuff!  Then we also got Endura for molding body panels such as the front of the 1980 Camaro.  It was flexible, somewhat lightweight, and could take some abuse without permanent damage.  But, now, there are various types of plastic in a car to accomplish  almost  everything  we  just  mentioned.    There  are 13 types of plastic currently used.  As examples, think of the black plastic that you typically find around fenders: it’s somewhat slippery and scratch resistant.  But the composite plastic of an SUV rear wiper is hard, almost like steel, and if you break it, the appearance is somewhat granular. On the interior, you find soft-touch plastic that you may believe to be a fabric over some other hard surface.  There is clear, and colored plastic depending upon the desired appearance or if the intention is to have light pass through it such as your climate control buttons. 

Plastic has other valuable properties as well.  Plastic is a good insulator for electrical components. It’s a good insulator from heat and cold hence the plastic lined door panels (on the inside where you don’t see).  Because  of  the  Insulation from heat, it is commonly used for intake manifolds on the engine.  You will even find it being used as coolant piping.  Radiator tanks attached to the ends of radiators employ plastic.   This  is  an  improvement  over  the old ones where the two dissimilar metals would corrode at the contact point.  Plastic doesn’t corrode.  (I know, if you ever worked on an old Ford, you can count on the plastic electrical connectors breaking from becoming brittle).  

Part of why plastic is used on vehicles is also to reduce weight, and less weight equals less fuel consumption, and therefore, fewer emissions.  Plastic is also used to increase aerodynamics of a car or truck.  Now you find a variety of plastic covers underneath a car to make the bottom side smoother, which allows the  air  to  move  underneath  with  few eddy currents of air to restrict it’s movement.  Here is an extreme example: 2005 Dodge 2500 4×4 takes 22.5 hp to move it through the wind at 50 mph.  A 2005 Malibu is around 12 hp for the same conditions.  The differences are obvious.  But, it’s the use of plastic that can improve a vehicle’s aerodynamics to reduce fuel consumption.  Take a look at any hybrid truck, like a Tahoe, and you’ll see the difference in its use of plastic to improve its movement through the air.

Let’s take closer look under the hood.  You’ll find plastic shrouds to direct air under the hood, plastic covers to keep the weather out of fuse panels, plastic hose connections, plastic fuel hose, plastic pulleys, even a plastic oil pan on some vehicles.  You won’t need to ever worry about that pan rusting through and seeping oil!  

One last thing about plastic: many of those plastic parts are made from recycled plastic, and once the end of life of the car is at hand, those plastic parts can be recycled again (hopefully, depends on the scrap yard).  Many manufactures, such as BMW and Lexus,  have that as their intent with their selection of vehicle materials.  

Enjoy your plastic interior!  Ž

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