Penned by Paul Bracq as a successor to the E9 Coupé, the sharp 6-series was launched in 1976. The earliest examples were built by Karmann, and initially sold with a 3.0-litre straight-six as the 185bhp 630 CS (not available in the UK), or a 200bhp 3.2-litre – borrowed from the range-topping 3.3 Li saloon – in the fuel-injected 633 CSi. BMW offered four-speed manual or automatic transmissions, and a five-speed manual soon followed. The underpinnings were a development of those found under the E12 5-series, which meant MacPherson struts up front and semi-trailing arms at the rear.

Within the first 18 months, BMW took production of the 6-series in-house at its Dingolfing plant, although Karmann continued to manufacture the bodies. In 1978 the 633 CSi was replaced by the 635 CSi, complete with a new 218bhp 3.5-litre engine. Thanks to its new close-ratio five-speed gearbox, it could hit 60mph in 7.4 seconds and go on to 140mph, although the automatics were slower. 1978 saw the introduction of a new entry-level model, the fuel-injected 628 CSi.

1982 marked a huge turning point for the BMW 6-series, as it received a major mid-life facelift. Gone were the slender bumpers; in their place a far more modern-looking deep bodykit, matched with larger wheels. Inside, the dashboard was updated, with a new three-spoke steering wheel. The changes were more than skin deep, too, because the older E12 suspension was updated with a far superior E28-based set-up. The engine line-up was also upgraded, with a more efficient 3.4-litre now fitted to the 635 CSi. From 1983 an improved four-speed gearbox was fitted.

The most exciting version came in 1984 with the introduction of the M635 CSi. European-spec versions were powered by a slightly revised version of the M1’s 286bhp M88 engine, which took the 6-series into the big leagues with a sub-7.0sec 0-60mph time and a 158mph top speed. Although sold in the US as the M6, this version wasn’t fitted with the full-fat engine due to emissions regulations – there was a less potent 256bhp S38 engine. The US-spec bumpers were adopted for the Highline models in 1987.

Production of all models ended in 1989, making the E24 the longest-lived BMW of all time. It wasn’t directly replaced, although the 8-series took over the mantle of flagship BMW coupé when it was launched in 1990.