Opel Diplomat classic car for sale

Introduction and history of the Opel Diplomat

The Opel Diplomat represented Opel’s ambition in the upper market segment from 1964 until 1977, succeeding the Kapitän P 2.6 and continuing alongside the Admiral. It shared its underpinnings and body with the Kapitän and Admiral, together known as the KAD series. Consciously developed for the prestige class, the Diplomat aimed to rival established luxury benchmarks. Its external features borrowed cues from American GM contemporaries, while its interior exuded a distinctly German sense of comfort and meticulous quality. Production concluded with the Diplomat B in 1977, marking the close of Opel’s full-sized segment era.

Model history

The Diplomat A launched in 1964, distinguishable by its 'Diplomat V8' fender script and tailored grille details. The series B followed in 1969, featuring restrained exterior lines consistent with the style of the 1970s. Variants included four-door saloons and a rare coupé version by Karmann, with just 330 units built. While the Kapitän exited the market by 1970 and the Admiral bowed out in 1976, the Diplomat remained until July 1977. Its predecessors were the Opel Kapitän models, and no direct successor continued the Diplomat’s tradition after its discontinuation.

Highlights of the Opel Diplomat

The Opel Diplomat stood out in the executive car market with standard features uncommon at the time, such as power steering, advanced automatic transmissions, and a range of large-capacity engines. The flagship’s interiors often showcased high-quality wood trim and, at extra cost, luxury materials like leather, which elevated the car’s ambience. Electrical amenities such as power windows and rear window defoggers further underscored its focus on comfort. Despite low production volumes, the Diplomat boasted sturdy construction, impressive road presence, and a solid reputation for durability. Many examples survive today as well-preserved survivors with original documentation and accessories.

Technical data

Special Editions and Collectible Models

The rarest and most prestigious Diplomat was the two-door Coupé built by Karmann from 1965 to 1967, of which only 330 were delivered. This exclusive variant offered a vinyl roof, optional leather upholstery, and performance on par with luxury sports coupés of the era like the Porsche 911 and Mercedes 280 SL—but with a much higher price tag. Today, surviving examples of the Diplomat Coupé are sought after due to their low production numbers and unique status within the range.

Engine and Performance, Transmission and Handling

In everyday driving, the Diplomat’s large V8s delivered smooth power and ample torque, ideally suited for fast motorway travel as well as relaxed, long-distance cruising. The A-series’ 4.6-litre V8, sourced from General Motors, initially suffered from thermal issues under sustained Autobahn speeds, leading to a switch to the more robust 5.4-litre version. The B-series introduced a sturdy 2.8-litre six-cylinder as a more economical alternative. All variants offered comfortable suspension and power steering as standard, making the large saloon notably manoeuvrable for its size. Transmission options were mainly automatic, which contributed to refined driving characteristics. Spare parts availability remains decent thanks to many preserved examples and an active enthusiast network. - Diplomat A V8 (1964–1968): 4.6L V8, 190 PS, Powerglide automatic

• Diplomat B V8 (1969–1977): 5.4L/5.6L V8s, up to 230 PS, 3-speed automatic
• 2.8-litre B-series (carburettor or injection): 140–165 PS, for those seeking lower running costs

Interior, Comfort, Exterior and Design

The Diplomat’s design was shaped by international influences—with a stately silhouette reminiscent of American GM sedans but refined for European tastes. The cabin featured real wood details, a distinctive two-tone steering wheel, and chrome finishes throughout. High-grade upholstery options, including fine cloth and leather, were complemented by features such as a centre console-mounted gear selector and power window switches placed in easy reach. The sedans presented understated elegance, while period colour palettes allowed for both understated and bolder choices. The Coupé variant, with its fastback line and available vinyl roof, showcased additional exclusivity. Other period features included optional alloy or steel wheels, and accessories such as electric aerials and special radio units, further personalising the vehicle.

Other relevant features

Many surviving Diplomats retain their full complement of original documentation, service record books, spare keys, and factory brochures, making provenance research straightforward. Generously sized boot spaces accommodate spares and accessories. The model’s solid build ensures that well-kept examples, especially those with period-original finishes and details, offer tangible connections to the era’s premium motoring culture.

Summary

The Opel Diplomat remains a fascinating artefact of German automotive luxury from the 1960s and 1970s—offering spacious comfort, strong engines, and a distinctive blend of US and European styling cues. With the B-series especially sought after, and the Karmann-built Coupé prized for its rarity, the Diplomat endures as both a practical classic and a collector’s showpiece, especially when found with period details and in original specification.