Used buying guide: Mercedes Benz SL500 R129

1 year, 2 months ago - 17 November 2021, autocar
Used buying guide: Mercedes Benz SL500 R129
The V8 version of the R129-era SL matches superb styling with touring credentials and plenty of power. We reveal what you could be letting yourself in for

The much-loved Mercedes Benz SL has been with us since 1954 and has just been rejuvenated for 2022 with a soft top, a stonking great V8 and standard all-wheel steering.

But even the cheaper SL 55 variant is set to cost around £100,000, so it’s hardly an everyman option. No matter, you needn’t break the bank for a soulful V8 cruiser with that covetable SL badge; you just need to do your research, be patient… and probably invest in a good toolkit. 

We’re looking at the range-topping 500 SL of the R129 generation, which is widely regarded as one of Stuttgart’s finest designs and is quickly approaching classic status. 

Bruno Sacco’s instantly recognisable angular silhouette, with its long, low bonnet and cab-backward stance, is made to look all the more purposeful on the V8 variant, which topped the line-up until the arrival in 1992 of the V12-powered 600 SL, for which you will have to pay a hefty premium today. 

The R129’s wide selection of potent and reliable engines won buyers of all means, but the thumping 5.0-litre V8 is the pick of the bunch. It packed 322bhp and offered a 0-62mph time of 6.4sec, enabling it to go toe to toe with the Ferrari 328 GTS.

At launch, it cost a hefty £58,045 (about £150,000 today), yet of the 204,940 R129 SL examples sold, 79,827 wore a 500 badge. 

The 500 was a soft-top as standard, claiming fame as the first Mercedes to have a button-operated hydraulic folding roof, plus buyers were given a manually detachable hard top. 

Electronics replaced lots of the old R107 SL’s manual functions for added luxury and enhanced safety. Notably, the R129 was the first production car to feature seat-integrated seatbelts and the convertible the first to feature an automatically deployed roll bar. So it’s safe enough to take your kids out in if you can find one with the optional rear seats, but fair warning: they had best leave their legs at home. 

For 1994, the 500 SL was renamed the SL 500; a 1995 facelift brought revised front wings and bumpers and the addition of side airbags; and 1996 ushered in options including a sunroof, rain-sensing wipers, front occupant detection and a Sport pack with bespoke styling and 18in wheels. 

A second facelift in 1998 added a new steering wheel, curved taillights, 17in rims as standard, nappa leather seats and body-coloured door handles. More important, the V8 was swapped from the 32-valve dualcam M119 unit to the 24-valve singlecam M113, which reduced power to 298bhp but is regarded by many as the superior engine, courtesy of its lightness and enhanced efficiency. 

The R129 wasn’t short on special editions, either. The ultra-exclusive Mille Miglia edition was launched in 1995 to mark the 40th anniversary of Sir Stirling Moss’s iconic 1955 race win, for example, and 100 Silver Arrow Editions were built in 2002 to honour Mercedes’ 1930s grand prix racers. But both are uber-rare on the used market, so don’t hold out for one.

Bruce Greetham, The SL Shop: “The appeal to most new buyers of the R129 SL 500 model is the easy roof operation with a flick of a button – the feeling of something expensive and good quality – combined with the smooth performance of its V8 engine.

"The linear power delivery is seamless throughout the gears. It will be a car you will drive less often but is more special. Most feel it’s the only model worth having, courtesy of its V8. As for which car ticks all the right boxes, it’s mainly determined by colour, condition, history and mileage.”

Buyer beware… 

Engine: The oil-supply tubes to the camshafts can blow, causing heavy tapping. The wiring looms on early examples can degrade, causing an engine misfire and other electrical problems that are expensive to fix and sometimes lead to wider ignition problems. 

Interior: Trim pieces can wear and the leather (including the nappa in later cars) might need replacing. Make sure all the gadgets work too, including the odometer, heater panel display, electrically adjustable seats and roof release. Also check the roll bar raises properly in case it’s ever needed. 

Suspension: The SL 500 tipped the scales at 1880kg, so check the suspension top mounts, dampers and springs for signs of a life hard lived. Be wary of any original components. 

Roof: The hydraulic roof mechanism is prone to locking up, but it’s an easy fix if taken to a proper mechanic, while damp in wetter climes can corrode the electrics. The roof controller module can also fail (it’s expensive to replace) and the hydraulic rams for the roof mechanism can leak onto the header rail and prevent proper operation. 

Electronics: Faulty air-conditioning systems and heated seats are expensive to put right so can fall by the wayside. Buy the best replacement parts you can afford and use all devices regularly to exercise all the moving parts. The anti-lock brakes and traction control can sometimes fail and are very difficult to trace, even with diagnostics. 

Also worth knowing

The SL Shop says buyers should look out for design specifics when identifying post-1998 cars, which feature chrome rings around the dials and a four-spoke steering wheel with a chrome star in the airbag centre. Beware inconsistencies and ask for any missing parts.

How much to spend 

£8000-£9999: Early coupé and soft-top models, some well on their way to 200,000 miles. £10,000-£11,999 Lower-mileage examples, such as a 2000 car that has done 88,000 miles. 

£12,000-£14,999: Some fine examples with clean bodywork, but look out for weary mechanical components.

£15,000-£19,999: Models in rare colours and with lots of options. Plenty with less than 70,000 miles and in excellent condition.

£20,000 and above: Sub-30,000-milers, often fresh from a dry, heated garage and with yards of paperwork. 

One we found

Mercedes-Benz SL 500, Limited Edition, 1999, £9950: This is a nine-owner car, but it has a full service history for peace of mind. If something goes wrong, it comes with a parts warranty for three months and 12 months of roadside assistance.

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