Their first car was completed in October 1902, the 10 hp (7 kW) Cadillac. It was practically identical to the 1903 Ford Model A. Many sources say the first car rolled out of the factory on October 17; in the book Henry Leland — Master of Precision, that date is shown to be October 20; another reliable source shows car #3 to have been built on October 16. In any case, the new Cadillac was shown at the New York Auto Show the following January, where it impressed the crowds enough to gather over two thousand firm orders. The Cadillac's biggest selling point was precision manufacturing and, therefore, reliability; it was simply a better made vehicle than its competition.

In February to March 1908, three Model K Cadillacs (1907 production) were released from the stock of Frederick Bennett (UK agent for Cadillac) at the Heddon Street showroom in London to compete in the annual Royal Automobile Club's Standardization Test. They were driven 25 miles to the Brooklands race track at Weybridge where they completed another 25 miles (40 km) before being put under lock and key until Monday March 2, 1908 when they were released and disassembled completely. Their 721 component parts were scrambled in one heap; 89 parts requiring extreme accuracy were withdrawn from the heap, locked away at the Brooklands club house and replaced with new parts from the showroom stock. Using only wrenches and screwdrivers the 3 cars were re-assembled and on Friday March 13 they completed a mandatory 500 mile (800 km) run. On completion of the test, one of the cars was placed under lock and key where it remained until the start of the 2,000 miles (3,200 km) Reliability Trials, several months later. It came out the winner of the R.A.C. Trophy. Parts interchangeability could not have been proven in any other more appropriate way. As a result of these tests, the Cadillac Automobile Company was awarded the Dewar Trophy for 1908 (actual award date was February 1909). The Dewar Trophy was an annual award for the most important advancement of the year in the automobile industry.

Automobile stylist Harley Earl, whom Cadillac had recruited in 1926 and who was to head the new Art and Color section starting in January 1928, designed for 1927 a new, smaller "companion" car to the Cadillac which he called the La Salle, after another French explorer, René Robert Cavelier, Sieur de La Salle. That marque remained in production until 1940.

 General Motors

Cadillac was purchased by the General Motors conglomerate in 1909.

Cadillac became General Motors' prestige division, devoted to the production of large luxury vehicles. The Cadillac line was also GM's default marque for "commercial chassis" institutional vehicles, such as limousines, ambulances, hearses, and funeral home flower cars, the latter three of which were custom built by aftermarket manufacturers. Cadillac does not produce any such vehicles in factory.

Pre-World War II Cadillacs were well-built, powerful, mass-produced luxury cars, aimed at an upper class market, below that of such ultra-exclusive marques such as Pierce-Arrow and Duesenberg. In the 1930s, Cadillac added cars with 12- and 16-cylinder engines to their range, many of which were fitted with custom coach-built bodies; these engines were remarkable at the time for their ability to deliver a combination of high power, silky smoothness and quietness.

In 1932, after Cadillac suffered from record low sales and charges of discrimination against black customers, Alfred Sloan created a committee to consider the discontinuation of the Cadillac line. At a fateful board meeting, Cadillac president Nicholas Dreystadt heard that legendary boxer Joe Louis could not go into a dealership to buy a car, because he was black, and resorted to having a white friend make the purchase for him. Dreystadt gave the GM Board of Directors a 10 minute speech in which he advocated advertising to black consumers so as to increase sales. The Board agreed to give Dreystadt 18 months to produce results. Cadillac managed to survive the Great Depression only by being carried along by Chevrolet, GM's low-priced, high-volume car. By 1940, Cadillac sales had risen 10-fold compared to 1934, thus saving Cadillac from going out of business.

The year 1934 brought about a revolution in assembly line technology. Henry F. Phillips introduced the Phillips screw and driver onto the market. He entered into talks with General Motors and convinced the Cadillac group that his new screws would speed assembly times and therefore increase profits. Cadillac was the first automaker to use the Phillips technology, which was widely adopted in 1940.

Despite record sales in 1973 and again in the late 1970s due to the popularity of the DeVille and Eldorado, Cadillac suffered from the malaise that set in to the American auto industry in the late 1970s to the late 1980s, primarily due to downsizing of cars in responses to fuel economy mandates following two energy crises. There were high points, such as the launch of the front-drive Eldorado in 1967 as a personal luxury coupe, with its simple, elegant design — a far cry from the tail-fin and chrome excesses of the 1950s. However, the 1970s saw vehicles memorable for excesses in dimensions and engine size before the downsizing era set in later in the decade. The new generation engine that debuted with the 1968 models at a displacement of 472 cubic inch V8 [7.7 liter] was designed for an ultimate capacity potential of 600 cubic inches. Displacement was increased to 500 cubic inches [8.2 liter] for the 1970 model Eldorado, then adopted across all models for 1975 but performance waned after peaking at 400 horsepower in the first year and declined in 1971 and later years due to reductions in compression ratios necessitated by the advent of low-octane unleaded fuel and increasing stringent emission requirements that further sapped performance and fuel economy.

 Seville introduction and downsizing

The compact Seville was introduced as a 1976 model and used a fuel-injected version of the Oldsmobile 350 as its only engine. For the 1977 downsized full-sized cars and Eldorado, the engine stroke was reduced to that used in the 472 and the bore was reduced as well, yielding a capacity of 425 cubic inch displacement. The bore was further reduced for 1980-1981 to provide 368 inches, again sharing the stroke of the original 472, as well as the weight and physical bulk. The build quality also fell short when measured against German rivals.

As with most American brands, Cadillac was forced to downsize its offerings between the 1973 and 1979 fuel crises. Its staple De Ville and Fleetwood lines were downsized for 1977 and again for 1985 when the cars also changed to a front-drive configuration. A downsized Eldorado debuted in 1979 with a new bustleback Seville sedan introduced on the same platform in 1980. Both the Eldorado and Seville were further downsized in 1986 into the compact car class, with sales going down the tube due to loyal Cadillac buyers being repelled by their smaller size and high price tags along with styling that resembled much cheaper GM cars such as the Pontiac Grand Am and Buick Skylark.

 

"Look-alike, drive-alike syndrome" and Lincoln's response

The "look-alike", "drive-alike" syndrome that affected most General Motors divisions under the administration of Roger Bonham Smith would have a devastating effect on Cadillac as it tried to downsize its models. The Seville, a generally successful model for Cadillac, would receive a disastrous redesign in 1985 for the 1986 model year that made the car heavily resemble its platform mates, the Buick Electra and Oldsmobile 98. Its coupe relative, the Eldorado was hardly distinguishable from the Oldsmobile Toronado and Buick Riviera.

In late 1985, Cadillac's domestic archrival, Ford Motor Company's Lincoln division, ran a series of ads that ridiculed General Motors and Cadillac terribly. The ad, referred to as "The Valet" depicted a couple leaving a function asking a valet to pick up their Cadillac, presumably the aforementioned Seville. The hapless valet instead retrieves an Oldsmobile 98. Once the car is retrieved, another gentleman confuses the Ninety Eight for his Buick. A commotion then starts, with owners of Buicks, Oldsmobiles and Cadillacs unable to distinguish whose car is who's. Suddenly, the owner of a Lincoln arrives out of the blue with the line "The Lincoln Town Car, please," which was greatly distinguished from Cadillacs and other GM cars due to its much larger (traditional) size and distinctive styling. Each of the ads ended with the tagline "Lincoln, What a Luxury Car Should Be." The ads, which led to record sales for Lincoln, also reportedly embarrassed the top executives at Cadillac and GM's 14th Floor, leading Smith to ask Ford to drop "The Valet" ads for Lincoln. Donald Petersen acquiesced, in the light of a severe downturn at Cadillac, and the general code of congeniality between the Big Three auto executives.

Due to gasoline shortages, Cadillac offered an Oldsmobile V8 engine that used diesel, the 'LF9' 350-cubic-inch (5.7L) V8 engine, in its full-size cars from 1979 to 1985. Similar in appearance to the gasoline engines from which they were developed, they used much thicker and heavier castings, and a higher quality alloy was used for their block and heads. The main bearing journals were also increased to 3.000 inches in size to compensate for the higher operating stresses and pressures that diesels exert on their reciprocating parts. However, this engine gained a reputation for unreliability, mainly due to its inability to withstand the effects of the poor quality of the diesel fuel available at the time. The fuel system did not have an effective water separating system, and neither the buyers nor the dealer service staff were adequately informed about the products and procedures necessary for the proper maintenance of the engine. This led to corrosion in the fuel injection pump, leading in turn to incorrect injection cycles, cylinder head lift, stretching or breaking of cylinder head bolts, failure of head gaskets, hydro-lock from coolant leaking into the cylinder, and the breaking of engine components, thereby causing catastrophic engine failure. In the hands of an experienced diesel operator, these engines can (and often do) travel for hundreds of thousands of trouble free miles. However, for a society of people who just "gas and go", this engine was particularly ill suited to the task. Ironically, Detroit Diesel, another division of GM, had had decades of experience building Diesel engines.

In an attempt to extend its brand further downward to appeal to younger buyers, Cadillac launched the compact Cimarron in MY 1982. The Cimarron shared the J platform with the Chevrolet Cavalier, Buick Skyhawk, Oldsmobile Firenza, Pontiac Sunbird, Holden Camira, Isuzu Aska, and Opel Ascona, and was expected to rival the BMW 3-series^{[citation needed]}. As the Cimarron was rushed to production about three years ahead of schedule, only a four-cylinder engine was available (a V6 arrived in 1985) and, at first, minimal styling differences were made to distinguish it from the considerably cheaper Chevrolet version. Buyers generally dismissed the Cimarron as a "warmed-over Cavalier" with leather seats, although Cimarron came with a hefty list of standard equipment and options, several of which were unavailable on Cavalier or Sunbird. Styling became much more in tune with other Cadillacs in its later years, but sales did not significantly improve after its initial rejection and it was discontinued in 1988. Although the motoring press lauded the first Cadillac manual transmission in decades (a four-speed stick in 1982 and five-speed beginning in 1983), the automatic's extra cost rankled buyers.

V8-6-4

Another perceived low point during the early 1980s was the variable displacement engine, branded the L62 V8-6-4 engine. Introduced in 1981, this 368 in³ (6.0 L) engine sequentially shut down cylinders as demand dropped. Company marketing hailed the engine as cutting-edge technology, but it proved unreliable and was dropped the next year in favor of a family of smaller aluminum V8 engines rushed into production. The 4100 (4.1 L) V8 engine was used widely in Cadillacs in the late 1980s. It suffered from coolant leaks, warped intake manifolds and warped heads. The 4100's problems cost Cadillac the loyalty of many customers.