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Rev up your engines!
It's time for the Scotty Kilmer Channel
today I'm going to talk about why certain car parts should never be made
out of plastic, but many manufacturers are doing just that,
now I understand that plastic is much easier and cheaper to make, this is a
plastic thermostat that I had to change out on this Ford because it broke
already, now even though this Ford is only six years old, the thermostat inside here
cracked and broke cause it's made out of plastic, while the thermostat of this 24
year old Toyota Celica is still strong, it's never been changed, the housing is
made out of metal, they can last forever so why did they make this thermostat
housing out of plastic, it's just cheaper, plastic is made by injection
molding, the plastic can be moulded and then they can make a whole bunch of these
things at once, when they break the mould apart, you just have to take little
tangs off, it's ready for use, while in a metal thermostat, they have to make good
moulds, it has to be poured, and then a lot of times when it comes out it's got
to be polished so it fits right, costs a lot more money, even though they last a
lot longer, now plastic bumpers they're okay, they're just out in the air, they
can bend and flex you can hit people, they can bounce back up, that's okay but
you don't want plastic where's the corrosive atmosphere, as I'm quoting from
a scientist here, research shows that the exposure of plastics to liquid chemicals
tends to accelerate their breaking, but when you have a thermostat that's hidden
inside the engine here, it's all hot, it's got all kinds of chemicals in it from
the antifreeze, of course it's going to break down relatively fast, and in the
case of this Ford, to add insult to injury, there's a little rubber hose that
comes off the thermostat housing, but what does it go to, yet another plastic
hose, and this plastic hose carries coolant, the plastic just degraded and it
had to be replaced, now this hose used to be made out of
metal, of course it's cheaper to make out of plastic, but then the heat and the
chemicals in the antifreeze eventually break down, and it'll start leaking and
you got to replace something that could have lasted almost forever, now plastic
has some good uses, in the old Saturn's they had plastic doors and plastic
fender panel, they don't rust, so that's an okay use
for plastic, but what about door handles, I spend hours every year replacing
people's door handles that are made out of cheap plastic, and they break when you
pull on them, when I was a kid, door handles were made out of chrome plated
metal, they basically lasted forever, now this is a Lexus, and though it looks like
it, it's chrome-plated plastic and these things break too, and they're a pain to
replace, in this case, be gentle and kind with the door handles, don't rip them up,
my wife has never broken any of these plastic door handles, because she's
cautious, but me, a lot of times I'm in a hurry and grab it and it breaks right
off and then you got to replace the stupid thing, when you're talking about
putting plastic under the hood of your car on the engine, where it gets really
hot, heat soaked over time, and there's caustic chemicals, that's just plain
stupid, for another example on this Ford, this is the power steering reservoir,
inside here there's a little plastic piece that goes to the top of the pump,
and they often break because it's plastic, what does plastic not like, chemicals,
like power steering fluid, temperature, it gets very hot with the power steering
pump, and pressure these things can put up 1,600 pounds per square inch pressure,
it's stupid to use any plastic parts on a power steering system, that reminds me
of a friend of mine who does Heating and Air Conditioning working on houses, he
said, Scotty you said cars are bad, we have heaters for houses that have plastic
parts inside the furnace, and guess what, after a few years the plastic melts we
got to take it all apart and replace it, sometimes it's just comical, look at
this, here's plastic valves inside here for the anti-pollution system, and what
did they do, they put a little heat shield to attempt to keep the heat from
bothering the plastic, like it's still under the hood of the car, it's still going to get
all kinds of heat in there and the plastic is going to degrade over time, I
swear sometimes it seems that they're making these things just so they'll last
a little bit longer than the warranty period, and then they don't care anymore,
now if there's no pressure stress like in an air filter box, there's just air going
through it, it's perfectly fine to use plastic, but plastic and pressure and
temperature again, not a good idea to use plastic, this radiator I had to replace it
because the top tank started to crack, got brittle, and was leaking coolant, I know
people are going to say, Scotty oh the plastic radiators they use them
because they weigh less, well they actually don't, because the plastic has
to be so thick that it won't crack right away
it actually weighs a little bit more than a thin metal, that can take a lot
more pressure and never wear out, you don't even get me started talking about plastic
headlights, when I was a kid they were glass, the glass stayed shiny forever, just
needed cleaning, this plastic stuff it gets all hazy, looks like crap, you can polish it, but then it will get hazy again
in a few months, but at least with exterior plastic you can use this
plastic polish to polish it and protect it, to make it last longer, but all the
mechanical parts under the hood, it doesn't do any good for that, because
they degrade from the inside out from heat and chemicals, believe it or not, a
man by the name of Mattie Holtzberg, made a mainly plastic copy of a Ford Pinto
engine, let's just say it's probably a good thing it was never put into actual
mass production, some people have taken this plastic in manufacturing a little
bit too far, and remember if you got any car questions just visit the Scotty
Kilmer channel, so if you never want to miss another one
of my new car repair videos, remember to ring that Bell!