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VIP Owned: 1988 Cadillac STS Prototype


One of the best parts about writing for Barn Finds is learning about cars that have snuck underneath my radar. This 1988 Cadillac STS here on eBay flagged by Barn Finds reader Jim S. is a rare bird, and said to be a prototype of Cadillac’s flagship sedan that would arrive on the market just a short time later. Color me surprised because I thought the STS’ arrival on the scene in 1992 coincided with the debut of the redesigned Seville – but this unusual prototype actually predates those new model introductions by a few years.  

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Largely reserved for executive usage, these STS models were rarely seen when new and hardly ever spotted today. That’s because they were originally rolled out for a very select group of owners, primarily consisting of GM executives, shareholders and other VIPs. The STS packed luxury, technology and handling into one attractive package, with a range of special features that included rear bucket seats, super thick carpeting, a fully-lined trunk compartment and leather and wood trim galore. This example also sports a digital dash panel and HVAC controls. Expert sources today estimate that only about 57 of these cars survive.

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Of course, the real story was the engineering. These early STS’ came fitted with GM’s FE2 Touring Suspension, a rear sway bar, unique wheels and tires and a faster steering rack. While luxury was top of mind for Cadillac, they also wanted to create a European-style driving experience. This impacted the styling to some extent, which was much more squared-off and taut that other domestic designs. Lots of color-keyed panels were on the menu, along with unique tail lights designed to invoke a sleek appearance. The 4.9L V8 cranked out 200 b.h.p., which seems downright anemic for an engine that size, but the domestic brands were still rebounding to some extent from the Malaise Era.

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There’s that incredible trunk, rich and warm with wall-to-wall carpeting. While the seller of this car isn’t shying away from typical sales hyperbole about how valuable this prototype STS will be in the future, I can’t help but take him a bit seriously. You could argue that with Cadillac’s ongoing goal of stealing sales away from BMW and Mercedes, the STS’ emphasis on handling capabilities and high-grade luxury makes it a historically significant vehicle, marking when GM saw the winds shifting and knew the old ways of building luxury cars would no longer suffice. With a Buy-It-Now of $3,999, it almost seems silly to not take the chance – at the end of the day, you’ll still have a terrific highway cruiser.


  1. grant

    I have a hard time getting excited about any GM product from the 80’s. Quality was terrible, and those interiors just bore me. Just my opinion. This one is priced fairly for a “rare prototype,” weather or not it will appreciate remains to be seen. To me it’s just evidence that GM should have known better.

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    • Steve Member

      If you believe that this is a GM prototype , then I have some swamp land in Florida for sale. GM made around 1500 for sale that year I call BS on the seller

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    • grant

      I don’t believe it, hence the quotes. It’s just an old used car with a leaky motor and crumbling interior trim.

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  2. GMSevicePartsOperations

    Nothing more than a Olds/Buick C Body…warmed over with upgraded grille and interior trim. As a matter of fact, the FE2 trim was actually badged on a few 80’s GM C body vehicles as a performance package prior. It fell on it’s face in sales numbers.
    Cadillac never intro’d anything into it’s line unless it mustered through Oldsmobile or Buick first, for sales numbers. That’s why this example, and those surviving are considered a “prototypes”. They are warmed over Olds/Buicks with low sales history. The LeSabre Coupe FE2 flopped.

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  3. fordfan

    Tip top of the line of general motors products and yet you will notice the plastic interior trim is fading at different rates.just look at the steering wheel

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    • FordSon

      C’mon fordfan….be realistic…how many door panels have you seen that did not see the effects of sun damage on Fords….I own 3 currently, not to mention over 10 over the years, and all have been subject to damage….not enough experience with them ?

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  4. Jay

    Ah, the Cadillac “sprinkler” model.
    Any gasket that could leak, did leak.
    What a job to pull the motor to replace gaskets that would just leak again.
    One of the few cars I refuse to work on ever again.
    Guys in the shop used to draw straws to decide who had to work on them, because they always came back…

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  5. piper62j

    All the Big Three had quality issues in the 80’s.. I remember a Ford advertisement for a piece of sheetmetal (quarter panel I think) where the announcer stated the quality and fitment of that quarter panel from a Fairmont would not be acceptable for the production of the current model he was advertising at the time.. Hmmm.. So Ford was screwing buyers in the 80’s with poor quality partsw and not in the 90’s.. Damn.. No wonder they almost went belly-up back then..
    Anyway, there are no NEW UNUSED 80’s cars left on the lots now, so they all sold..

    Decent find, nice car,,, Not worth it IMHO,,

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    • GMServicePartsOperations

      piper62j….Trust Me when I say….it wasn’t only Ford during those turbulent times….I worked for GM during the period that You refer to. I personally lived it, everyday.
      The Big Three suffered the wrath of the 80’s. We screwed GM customers in the 80’s with garbage parts just as much as Ford and Chrysler did…..It wasn’t Utopia by any stretch of the imagination…..don’t kid Yourself. I was there in the mix of it. All 3 suffered and they did what they had to do to stay afloat at the time. My job took care of My family. You would do the same if Your family’s survival depended on Your salary, and your salary alone….Wouldn’t You ??

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  6. GMServicePartsOperations

    FE1, FE2 and FE3 were simply General Motor’s Suspension Codes.
    On ANY 80-90’s GM vehicle….look in the glove box door (on trucks), or on the inside of the deck lid, or on the spare tire well cover (passenger vehicles) for a white tag with a black header labeled “Service Parts Identification” That tag identified how that specific vehicle was optioned, per build sheet, on the assembly line, by option code..
    FE1= Standard Suspension. FE2= Touring Suspension. FE3= Sport Suspension.

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    • GMServicePartsOperations

      Same applies to the Corvette ZR1, the Camero Z28, Truck Series Z71 “Off Road”, and on and it goes. They were badged from the GM SPO production line codes….That’s how they got their individual model names from GM….

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  7. RayT Member

    I would take the “rare prototype” claims with a lot of grains of salt. I knew and dealt with some people at the various automotive manufacturers back in the day and found that: a) they did not sell prototypes, for liability, government-regulation and tax reasons and b) prototypes that hadn’t been damaged beyond repair by ham-fisted journalists or beaten to death at the proving grounds were crushed at the end of their useful lives for the same reasons as (a) above.

    Oh, and if one did lay hands on an actual prototype: good luck finding a lot of critical replacement parts. Lots of hand-chewed unobtanium in there!

    I suppose a VIN check will tell the story, but I’d proceed with plenty of caution.

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    This car is very used with 124,000 miles on it and will never see $100,000 in any world it appears in.
    This seller is laying it on thick for that $2000 car.

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  9. GMServicePartsOperations

    No General Motors Prototype Vehicles have ever been released from factory confines except for Corporate authorized release to museums…. The Semi-production Prototypes that were released,with exception, were released to design team members and are closely documented and monitored by a specific historic division, as with all auto manufacturers. Long gone are the days of destroying prototypes for scrap….too many secrets at risk. Seriously? Come across a T-Type LeSabre Coupe and think it’s rare?…nope. Or maybe a 83 Riv Turbo 3.8 Convert and think it’s…..ummm, sorry….nope. I’ve got a 87 GNX with 6K on the clock…Oh, wait, “cough”..how much did You say You were asking?? Or maybe that ’86 Regal T-Type over there? Whats that going for? You’ll find Yourself cocking Your head like a dog…

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  10. piper62j

    Yes GM.. I was a Pontiac, GMC, Olds dealership service manager during those years.. It was a cheap time for the big three and that’s when the Japs and Germans were killing the big three..

    I agree.. I had to feed my family and did whatever I could to bring the bread home..

    That said, the big three have come a long way since then.. I just bought a new GMC Terrain Denali and love it to the max..

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  11. grant

    Personally, at my job that I work to support my family, I do the BEST job I can, to assure job security. But then, I’m not union either.

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  12. George Member

    If you’ve actually seen one of these cars, the interiors are sumptuous, and they avoid the tufted/pleated leather interiors and bordello detailing typical of Cadillac in the 80s Acres of leather, thick carpeting and I believe they advertised at the time, more interior wood than a Rolls Royce

    The exteriors were a little toned down too

    It’s certainly not a prototype and as stated above a couple thousand of were made before the new body came out in 91

    It was, however, is General Motors’ first attempt to make a Cadillac that might have a chance to compete with the import market and lead to today’s cars, and several areas.

    Last month there was a low mileage one that didn’t sell for 11,000.

    I suppose one day it could have some collector value, but we’re not there yet

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  13. Jubjub

    I have to admit, I kinda liked these. The bright red ones particularly. They looked nice without all the gingerbread, vinyl tops and wire wheels covers. The amber taillamps were a nice touch and the wheel wells were nicely filled. Too bad GM gave customers a choice instead of making them all look like this. Consumers were still stuck in the bad part of the 70s and their ideals were and still are foreign to me.

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  14. Nessy

    Prototype my butt and I am 100% sure. In November 1987 after reading all about the new Seville STS coming for 1988, my parents ordered a new black Seville with the special “new for 1988” as the dealer said, STS black out sport package just like this car, same wheels and all. The car was built in 2/88 and we picked it up in 3/88. Really neat car, moonroof and all. Alot of people did not care for the basic non chrome look on our Caddy but this was when they were still putting all those silly roadster tops and grill caps on every car that came into the lot. The only issue was a poor black paint job that looked like it was done with a spray can. When the car came in, my parents were so pissed off with the paint that they started walking out the door. The dealership asked if we could live with the paint if Cadillac took 3000 off the price of the car. I guess many other people were also not happy with the finish on their new Caddys. Well, we took the car and had it wet sanded and buffed to remove all the orange peel which helped alot. Oh, it’s not a 4.9 200 hp. This car has the new and very improved 4.5 155hp engine. The 4.9 came out for 91. Nevertheless, both the 4.5 and 4.9 cars were pretty fast. A big upgrade for the 4.1 which was dumped along the Cadillac line for 87. Nice car yes. Prototype? No.

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  15. Nessy

    I wrote the guy asking why he thinks his car is a prototype and explained how I had the same exact car with a 2/88 build date when he claimed his car was the first one with a 6/88 build date. Of course, he never responded. He must know his auction is based on BS. If anyone buys that car based on what he claims, they are not going to be pleased if they find out. Oh well.

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  16. krash

    (Seller’s claims)……Proto-posterous!!…..

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  17. Jack R. Christen

    Ok, here’s what I know about the 1988 Cadillac Seville STS. Sometime in the spring 1988 Cadillac Division contracted Cars And Concepts of Brighton, Michigan to create 1499 STS models. Mine, the one I have had since it was new was built on Wednesday, June 22, 1988. It was introduced at the 1988 Detroit Grand Pri and that was the first public showing of the vehicle. It was then distributed, one for each dealership and some for industry executives. The list price on mine was $34,951. Now that was quite a price for an American made car in 1988. It was painted White Diamond with Beechwood Hand Stitched Leather interior with Burled Elm Wood interior trim, NO plastic trim. The STS option was listed as an additional $6,223.00 plus the Bose Radio system was $576.00 over the base price of $27,627.00. The exterior of the car was modified quite extensively by Cars and Concepts, which was owned by Dick Chrysler of Hurst fame. The front fenders had the side lights removed, the grille was changed, the hood had the ornament removed. The chrome side trim was removed and replaced with car color body solid side moldings. The tail lights were redesigned and fiber optics carried the lights into a display above the rear window package tray. The interior was modified to seat only four adults with the rear seats separated by a center console and storage unit. The dash is electronic and featured one of the first computerized control and monitoring system. The trunk area was completely carpeted including the inside of the deck lid. It came with 15″ Goodyear Eagle GT+4 black tires and 15″ Aluminum Wheels. 3.33 final drive ratio, disk brakes with anti-lock braking system. It was the first GM car to win the J. D. Power QS9000 quality award. I can tell you that the 1988 STS drives and rides better than my SRX hands down…

    Like 1
    • Robin

      Jack, my Dad has that exact car your talking about and would like to sell it before he dies, he’s 91 now. He bought it at a deanship, and has 100,000 miles on it. Its red, with red leather interior I think its been awhile since Ive been in it. I would just like a fair price for it, he tells me there were only. 1400 made.

      Like 0

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