Why don't automakers use plastic body panels like the Saturn's any longer?
 

I was just looking at used car listings and saw an old 94 Saturn SC1 for sale. It had 185K miles on it but no rust :p I'm guessing that the 1.9L engine was shot because the seller only wanted $1000 for it.

Did the plastic panels cost a lot more than steel? The price of sheet steel has shot up recently so I wonder if some of the automakers at looking at plastic again. Seems to me the car should be lighter with plastic also not overlooking the steel cage underneath them for structural strength.

i got my 91 SC for $2000...I freakin love the thing, runs like a champ, the only thing with the SC's is that when you idle you get a lot of engine vibration. It feels like the engine is misfiring but if you watch the RPM's it stays constant. I think the vibration is caused from where they mounted the engine to the chassis

anyway, I think the reason they went away from plastic was mostly due to safety concerns. I think those fears are somewhat unfounded though seeing as how the plastic body panel cars still have the steel cage. Maybe people didnt 'feel' safe. If anything I would think that the tin or aluminum body panels of today would be more dangerous from a laceration standpoint...not to mention the plastic doesnt dent! Nothing like having your hands full and not being afraid of kicking your door shut...

well if youve ever seen a plastic bodied car thats hit somehting the plastic just blows apart in chunks, or it cracks. so if you think about it while a metal pannel will have a small dent that can easily be fixed if a plastic pannel has a small crack it has to be all replaced...

very true..i guess the other side of the coin is durability, i had a friend that got into a minor side impact accident with an SL2 and what should have just been a new side panel turned into a lot more

I remember reading Saab in the early 80's made a prototype called the EV-1 which used memory plastic panels, so low speed impacts would not cost thousands in repairs and would self heal in seconds.

Plastics are getting so advanced, you can basically make an engine from plastic now.

Some of the early Saturn 1.9's had issues with the cylinder head cracking (there's one in my garage right now that's waiting for a new head).

They are nice looking cars though, and fairly aerodynamic too.

Plastic would be a big plus in the rust belt, assuming the car never was involved in an accident.

I am not familiar with the 91 but on the newer models the vibration you report is a strongh indication that the upper right engine mount should be replaced. Some replacement ones are a bit too firm also. I got one from Autozone that was cheap and nearly as soft as the orginal. On a 91 you might need a few more mounts but I don't think that shake is normal.

I'm not sure how things turned out for Saturns. But Honda actually tried plastic front fenders on their 1984-1987 CRXs. And the results were, shall we say, less than desirable. The problem was that, as the panels aged, they tended to fade, become brittle, and crack. As you probably know, plastic just does not stand up to UV. And this is something that no advances in plastics have yet been able to overcome. Until this issue can be overcome in some way, don't expect alot of plastic body panels.

yup, remember the rubbery plastics of the actual steel bumper cars bumper fillers? (went between the bumper and the car for looks, also when the bumper got pushed in it didnt hurt the steel car) mine on my chevette have all cracked off. what little is left is a fragile as glass...

In my trips through the junkyards, I see a LOT of late '80s, '90s and early 2000s Buicks, Oldsmobiles and Cadillacs with plastic front fenders. As far as I can tell, they seem to hold up very well, unless they get bashed. They seem to ward off the minor stuff just fine. I've seen some Saturns that have been in serious enough accidents to blow the airbags. They don't seem to have any more damage to the cab than any other cars.

Most of the cars I see are 10-20 years old. The plastic panels still look good. How plastic panels would hold up after 50 years I can't say. Since cars aren't designed to last THAT long, does it really matter?

As for the bumper fillers on Chevettes, Cadillacs (like mine), etc., those are made of a different plastic. And there are variations between manufacturers, also...on my '84 Town Car, the plastic fillers are still in perfect condition, but the fillers on my '83 Cad are falling apart. There's a mid-'70s Buick with Hysterical Vehicle plates running around locally with the plastic fillers pretty much gone (but the rest of the car is still very shiny!). The plastic fillers on Fords seem to hold up better.

From a body work perspective they are a thing of beauty. The panels are cheep and easy to install and never rust. I just looked up some pricing and replacement fenders are less than half what a metal fender costs. I have several friends that work in body shops and they all say that Saturns are the easiest to fix.

As to why more car makers don't use them? I don't know.

I wish the same could be said of my 1980 Buick:
https://lh4.ggpht.com/ronanian/R-Vyc9...6/IMG_0476.jpg
The first 10 or 12 years of its life were spent garaged out of the sun/UV, too.

i once jumped over a ditch in my kadett (mostely my fault...don't care to repeat that)... anyway, the car survived but the front did impact the ground, the ugly plastic bumper was ok, exept for a minor crack at the tow hook, but the radiator support beam behind it was all bent upwards.... however this sort of plastic can't be painted and it colors with age... still if the whole car colored that would still be cool.

also why not make a car from fabric! silly? bmw doesn't seem to think so
check out their gina concept
https://au.youtube.com/watch?v=kTYiEkQYhWY

hey thanks for the heads up! how do i go about diagnosing which ones need replacing. I'm gonna need to pull the engine for this one huh.

No reason to remove the motor- just use a jack under the oil pan to take the weight off the motor mounts as you replace them

the new smart cars have plastic body panels. to change the color of the car, all you have to do is buy the panels ($800) and change them yourself. if you are feeling lazy, you can get the factory to do it for another $400.

I am sure the panels all but explode on impact though.

As for the "no rust" take a closer look at the rocker panel (frame) and the chassis and suspension components, they're likely ROTTEN and broken even... my '96 Saturn has needed tons of the parts under it replaced due to rot and it only has 140k on it!

As for the engine vib. in the SC's... you need an engine mount, plain and simple.

For the Saab/EV1 comment, I've heard nothing about EV1 other than this:
https://en.wikipedia.org/wiki/EV1

It's GM based, essentially a Saturn.

Plastic is cheaper, that's for sure, but it is prepped differently than steel and many shops neglect to approach that topic when repainting panels. The front and rear bumpers on my white Saturn have been repainted due to minor bumper benders (oh, and since it's plastic, when you get into a VERY low speed collision, the paint explodes off the panel) and both bumpers are chipping away like the paint is 50 years old or something. There is no easy fix for this. Also, you don't always break a panel, sometimes the panels will just crack, which just like a windshield, tend to get worse and worse w/ heat cycles of summer and the frigid winters.

BUT... I have no door dings to speak of, and upon taking the door panels off to install speakers, it looks like they planned ahead for the collision testing and installed 2 horizontal braces and one diagonal brace in the door... I fear no side collision after seeing that.

how do i figure out which one needs to be replaced?? is there a crack or any other tell tale sign??

Plastic body panels don't bother me at all. My Camaro had plastic front fenders, and door panels and I didn't mind it at all. They weren't cracked, faded or worn in any way, and the car was straight as an arrow because you can't door ding it! :)

One of my good friends hit a deer with his Camaro and all it did was put about a 6" crack in the front fender. I was pretty impressed.

You beat me to it Beef about mentioning the Smarts have all plastic panels. They aren't too bad about exploding upon impact. They can take a hit better than metal any day.

Here's a pretty good wreck - or bad. However you look at it.

it's the upper motor mount, located to the left of the valve cover if you're staning in front of the engine... between the valve cover and the coolant resevoir.

$45 at Napa or $5 at junkyard. Sign up on saturnfans.com and learn the How-To, you need to loosen and re-torque a few nuts after you replace the mount. Do a search over there and you'll find everything you need.

do you have any pics of the whole car? i dont believe i know what a 1980 Buick looks like(looks smaller than i imagined)

Buick made a little Skyhawk that was the same size as the Chevy Monza

It's a Lesabre. It's huge, and I don't know how they fit all that room considering the relatively meager exterior dimensions. The trunk is big enough to park my VW in, as is the engine bay. The interior has pretty much the expected amount of room, but probably not as much as a model ten years older.

The curb weight is a post-1970s-gas-crisis meager 3500 pounds, making it far less dense than a modern car. For being so light, it still rides nicely like a yacht. For having a 1980 technology (hello emissions, nice to meet you) V6 with a messed-up carburetor, it also accelerates like a yacht.

https://lh4.ggpht.com/_oNsRR_T1Qx0/R-...8/IMG_0452.jpghttps://lh3.ggpht.com/_oNsRR_T1Qx0/R-...8/IMG_0456.jpg
https://lh4.ggpht.com/_oNsRR_T1Qx0/SF...0/IMG_0822.JPG

ooh yea thats the car i was imagining, my uncle had and 83 he bought for $300 one time :P

The drawback of trusting wiki when real information is out there.
https://www.saabhistory.com/2007/06/2...cle-ev-1-1985/
based on the 900 and used steel body panels

My plastic (glass reinforced polyester) bodied 1969 Saab Sonett looks nearly perfect, but the chassis (welded steel panels) needs constant care.
The first Sonett Super Sport (1956) has an aluminum chassis. The next ones were steel. Everyone of that first generation is still (or again) in museum quality. There were only 6 of these model "94" built before the competition class rules were changed and made them obsolete.

The EV-1 was actually made by Saab in Sweden, before GM killed that car, it has nothing to do with the Saturn trust me, Wiki gives very biased and reductive information, it has no depth of knowledge at all and it gets edited by every neoconservatives Tom, Dick and Harry.

The EV-1 was actually made by Saab in Sweden, before GM killed that car, it has nothing to do with the Saturn trust me, Wiki gives very biased and reductive information, it has no depth of knowledge at all and it gets edited by every neoconservatives Tom, Dick and Harry.

As for plastics not being able to withstand UV that is not true, some plastics have a half life of 500,000 years! the reason some plastics fall apart is economics, cheaper is better, they called it designed obsolescence, they want the car to fall apart so you buy another one with brand loyalty.

Their designed obsolescence is a lot more effective on plastic than it is on steel. That's an observation, not a theory. We can talk theory all we want here, but the fact is...the steel they use lasts a lot longer than the plastic they use, or at least it did back in 1980. I suspect that it is different on newer vehicles and also more well-protected by paint.

Wiki has the Saab EV-1.

I never said it didn't exist, I just said that's the only thing I had ever heard of.

sheesh

The plastic used for the bumper inserts on your Buick, and on my '83 Cadillac (which are falling apart also) are a very different kind of plastic than that used on front fenders of Camaros, Saturn bodies, Olds Silhouette vans, etc. It seems to me to be related polyethylene type plastic...the type like they make some kids toys which fade and crumble after a year two out of (e.g. "Big Wheel" trikes). The body parts are ABS plastic, which seems to hold up a lot better.


Note: I am neither an expert on plastics, nor do I play one on TV. If anybody out there is, please feel free to chime in!

A Honda repair foreman once told me that the 2001 Honda Accord was a horrible car to repair because it would deform all over the place compared to the older Honda's that had thicker chassis legs which didn't fold up like straws.

Japanese cars were terrible for rusting in the 70's and 80's, I think they improved in the 90,s and now in this decade there going backwards again, they peaked already and its probably down hill from here?