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

[jadziasman]

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 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.

[dutra2418]

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...

[VetteOwner]

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...

[dutra2418]

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

[ShadowWorks]

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.

[GasSavers_Erik]

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.

[usedgeo]

Originally Posted by dutra2418

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

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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.

[StorminMatt]

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.

[VetteOwner]

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...

[GasSavers_JoeBob]

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.