Mercedes-Benz SL R129 buying guide, history and model review

The R129 is a prime example. Sporting it isn’t, but there’s real depth to the driving experience. This generation of SL dates from MB‘s peak era for over-engineering, and offers serious value for money today.

Launched in 1988, this ultra-modern Bruno Sacco-designed convertible moved the game on hugely from the ageing ‘Bobby Ewing’ R107. Based on a shortened W124 platform and underpinned by multi-link rear suspension, it looked sharp and featured a whole host of cutting-edge safety and comfort features – notably a roll-over protection bar.

Three engines were offered from launch: two 3.0-litre straight sixes (a 188bhp 12-valve single-cam and 228bhp 24-valve twin-cam) with four-speed automatic or five-speed manual transmission, and the range-topping 500 SL, which was fitted with a 5.0-litre 322bhp V8. The monster 48-valve 6.0-litre V12 in the SL 600 toppled this in 1992.

Six-cylinder performance is reasonable, but you’ll want a V8 to make swift progress – plus it sounds much better with the roof down! There’s not a huge difference in economy between the two.

The naming convention changed in 1994, so the 300 SL became the SL 300, and a facelift in 1996 introduced more meaningful differences. Body-coloured bumpers updated the look and heralded a new five-speed automatic gearbox.

1998 saw the R129’s final facelift, with the straight-six dropped in favour of new M112 V6 engines, and the related M113 V8 for the 500. Larger wheels and various trim changes came, too. This was the era of Mercedes cost-cutting, so newer doesn’t necessarily mean more desirable.

The AMG versions deserve a separate guide of their own, as several different hot SLs were offered. Most common is the 6.0-litre V8-powered SL60, offered from 1993 to ’98, when it was replaced by the 5.4-litre SL55. Most highly prized are the V12s, in both 7.1-litre and ultimate 7.3-litre form – an engine that would later find its way into the Pagani Zonda.

It’s fair to say that the R107 was traditionally enjoyed by the older gentleman, but today the R129 is being appreciated by a younger, cooler crowd. After all, most are a set of AMG wheels away from being prime RADwood material.

Six-cylinder models are the entry point, and offer great value. A £6000-8000 budget should find a good selection of well-maintained cars with reasonable mileage. Unloved examples can be found for less than £5000. Low-mileage cars in excellent condition can command £10-15k; more for special examples.

For the V8, be prepared to spend a little more, with £8000-15,000 offering a spread of good-to-excellent examples, and the best upwards of £20,000.

Standard V12 models are few and far between, but expect to pay upwards of £40,000 for a top example. V8 AMG models range from £25,000 to £50,000; V12 AMGs are in a league of their own – the last SL73 sold at auction in 2024 for $610,000…

Correctly maintained six-cylinder engines are known to run for 400,000 miles without issue; just check for oil leaks from the head gasket. The V8s require a bit more attention, but are similarly rugged.

Mercedes changed the original ‘sealed for life’ gearbox fluid to 40,000-mile intervals, so ensure it has been replenished. Post-1993 SLs suffer wiring harness issues, so proof of replacement is good.

Expect supercar bills for V12s, especially those with the ‘Active Damping System’ suspension. Parts availability is generally good, but can prove expensive.