A Future Classic – The R129 SL Model Range: 1989-2002

Original Article Brian Clifton • Bud Cloninger

Revision & update Jason Burton • Gary Anderson 

Images Daimler Archives

Data Tables Daniel Stahl

Daimler AG uses the term “Young Timer” to differentiate future collectible-classics from the usual definition of a classic automobile as a vehicle out of production for 25 years (although cars with long production runs, such as the R107 SLs – 1971-1989 – became classics before the last models were 25 years old). The same logic holds here, as the first R129 SLs are now 28 years old. A benefit of the R129 SL is that these cars are modern in nearly every way; more recent models lack only some of the most sophisticated digital interfaces and turbocharged engines. From a driver’s perspective, these are exceptionally safe and responsive vehicles.

Background

The R129 premiered at the Geneva Motor Show in 1989 to rave reviews. With taut styling by Bruno Sacco, it looked the part of a sports car compared with the “boulevard cruiser” styling of its predecessor.  The rugged chassis was based on the W124 cars. With a removable hardtop it was as safe and secure as a coupe. With the hardtop off, the convertible soft top could be opened or closed electro-hydraulically in about 30 seconds, and safety features included a rollover bar that could pop up in 0.3 seconds when its control sensor detected an imminent roll-over. 

The SLs had ABS brakes and adjustable seat belts. All cars had driver airbags per federal law requiring them in cars produced after April 1, 1989. In 1995, all were equipped with Electronic Stability Program (ESP). Thus, there were modern safety features on these SLs throughout their 12 years of production.

At introduction in the United States for 1990, there were two engine choices: a 3.0-liter inline six and a 5.0-liter V-8. The engines were upgraded throughout production. A 3.2-liter inline six was introduced for 1994 models, but then discontinued in 1998 in the U.S. market. A 5.0-liter 24-valve V-8 was introduced in 1998 and continued to the end of production in 2002. Finally, a 6.0-liter, V-12 (as used in the 600 SEL sedan) was introduced to the R129 series in 1993.

Reasons to buy an R129

The R129s have a combination of styling, comfort, safety and performance that makes them an excellent choice for someone looking for a sporting, open-top, fun car for two. Given their age, the cost of acquiring one is likely as good as it’s going to get and their value can be expected to appreciate.

A removable hardtop is standard (not an extra-cost option) and provides coupe-like noise control, safety, and a superb environment for air-conditioning when it is needed in hot, humid climates. Further, with the hardtop removed, the convertible top can be fully opened with the touch of a button for open-air motoring, and the occupants still have the safety of that pop-up rollover bar in case it is needed.

The trunk is quite spacious for a two-seat roadster – especially when compared with the small trunks of the preceding R107s, and the R130 and later models when hardtops are retracted. If trunk space – or room for four passengers with luggage – is a big concern, consider the A124 E-Class or A208 CLK-Class cabriolets for top-down cruising.

Most critical parts are generally available through the Mercedes-Benz Classic Center USA and from other suppliers.

Reasons not to buy an R129

Biodegradable wiring harness and ignition wiring in 1993-1995 model years must be replaced (if not already done by a previous owner) to assure drivability and safety.

The removable hardtop requires two people or a hoist to remove and replace; it does provide coupe-like comfort and rollover protection at the price of being heavy.

There are several issues on the R129s that can be expensive to repair: head gaskets on early 300SLs; 5-speed automatic transmissions on 500SL/600SL models; failure of the LCD instrument cluster readouts and of mechanical odometers if reset while moving; and ASR automatic slip (traction) regulation  systems on 1990-1994 models before ESP became standard.

600SL/SL600 V-12 engines are expensive to maintain and repair. They have great performance and smoothness, but buyers should consider the benefits versus the costs of operation and maintenance.

Checkpoints

On SLs with staggered wheels (wider rear wheels and tires) replacements with high-performance tires (e.g., the Michelin Pilot Sport or equivalent) can be quite costly.

The Adaptive Damping System (ADS or ADS II) on SL600s, and optional on SL500s, can be very expensive to maintain or replace.

Check for presence of the wind-protection screen (in models dating from 1993), secured in the trunk by three straps, that minimizes drafts when the top is down and the car is driven at highway speeds.

The removable hardtop delivered with the car must be included. Due to changes in the A-pillar, hardtops are not interchangeable. Be sure to check that the hardtop fits the R129 being purchased.

If the data/build card indicates that the car came with a Panorama Hardtop, be sure it is available. These are difficult to replace and a different model may not fit due to A-pillar design changes.

Determine if it is a Special Edition, such as the Mille Miglia Edition, Designo Edition, 40th Anniversary Roadster Edition-1997, Special Edition-1998, Final Edition-2000, SL Edition-2000 or Silver Arrow Edition-2002. These editions include special features that may be difficult to replace due to limited production. Also, be aware that a limited number of 1990-1992 300SLs had a 5-speed manual transmission and this should be indicated on the Data Card/Build Card.

If the car is claimed to be an AMG model, buyer beware. It’s easy to buy logos and affix them to the body and the engine (the builder’s signature plate was not in use yet. There were only a few produced: SL55 (65 units); SL60 (633 units); SL70 (150 units); SL72 (35 units); and SL73 (42 units), and most are still in Europe.

Do a test drive with a knowledgeable technician who understands the multitude of electronic controls. Some of these functionality tests can be performed with the M-B Star Diagnostics System. And, finally, check the service records (from the seller or using the MBUSA’s “Vehicle Chronology: R129 SL Models–1990-2002 Vehicle Master Inquiry” system) to be sure that the SL has been regularly serviced.

What about the SL600?

The SL600, with an exotic V-12 engine that few manufacturers ever offered, has a cachet all its own, and when everything is working well, from the driver’s seat is an incredible car. Acceleration from 90 mph to 140 mph is the same as from 30 mph to 90 mph. The R129 chassis is up to the power of the V-12, which pulls hard throughout the speed range. And it’s a V-12 – almost no one else is making them any more.

However, the engine is not without its problems. From wiring harnesses to oil leaks, the engine had some issues that can be expensive to fix. The early R129 V-12s are likely to be problematic from an emissions standpoint, with a check-engine light that is almost always on. This warning light is normally a mechanic’s friend. However, on the V-12, it can indicate anything from plugged exhaust-gas recirculation ports to intake-manifold leaks to carbon-fouled air-injection ports. Trouble-shooting can be a time-consuming task.

Particularly, the M120 engine is essentially two six-cylinder M104-configuration engines sharing a single crank and has the same oil leak from the front cover. If unattended, the leaking oil will soak the right side of the engine, ruining the alternator and any coolant or air hoses in the vicinity. To repair the oil leak, the intake manifold must be removed to dislodge the front cylinder head cover to access the valve-cover gaskets. In addition, the engine wiring harness has to be disconnected from all the sensors and injectors. Updated intake gasket spacers will be needed, as well as replacements for every rubber air and crankcase hose, as well as all vacuum hoses.

These cars can be found for as little as $10,000, or even less for cars in poor condition, but don’t be fooled into thinking that’s a good deal; it’s more likely an indication that engine work needed to be done and the owner couldn’t afford the cost.

Buy an R129 or look for an R230?

The primary advantage of the R230 is that it has an integral retractable hardtop, which is considerably more convenient than the heavy and awkward removable hardtop on the R129. On the positive side, the panoramic roof that was a factory option on the R129 is amazing, offering ridiculously expansive views of the sky, much bigger than the panoramic roof on the R230.

The R230 cars featured the new Active Body Control self-leveling suspension. When it is performing properly, it is much superior to the Active Damping System on the R129s, though it can be extremely expensive to repair if it hasn’t been properly maintained and is not functioning.

In addition, there are several advantages of the R129 over the R230. For golfers, two full golf bags will fit in the R129 trunk; it is tough to even fit a drink cooler into the R230 when the top is folded away. The later V-8 R129 vehicles featured the M113 engine, for which several supercharging kits are available, but that is essentially the same engine as offered in the early R230s until the SL550 came out for model year 2007.

Deploying the electric soft top.

The mighty SL73 AMG, its hand-built V-12 making 525 horsepower, accelerates to 60 miles per hour in just 4.8 seconds.

The high-quality, contemporary interior of the R129 SL range.

The R129 exhibits all the hallmarks of a classic in the making. The deceptively simple design with its slightly wedge-shaped, honed body with flared wheel arches, standard alloy wheels and raked A-pillar displays a perfected blend of sport and luxury, comfort and elegance, true to the grand tradition of Mercedes-Benz.

CHRONOLOGY

1989    

Premiered at the Geneva Motor Show in spring 1989

1994    

First SL models with new designation (e.g., 500SL is now SL500)

1996    

Styling facelift • V-8 & V-12 upgraded to 5-speed electronic transmission; previous transmission a 4-speed

Bumper and side panels now body color 

Grille now with six slats rather than seven

Front fender vents updated; two rounded slots instead of three squared slots (behind front wheels)

Panoramic roof now an option

Xenon HID headlamps standard on SL600, optional on SL500

Clear front turn signal indicators

Addition of side airbags

1997    

Sensor to deactivate passenger airbag if seat held less than 26 pounds (for baby carrier)

Sport package option

Automatic rain-sensing windshield wipers standard

Built-in HomeLink programmable garage door opener

Climate-control panel replaced with new larger LCD control panel

1999    

Styling facelift

V-8 engine switched from M119 to M113

Body-color door handles

Side mirrors more rounded, similar to SLK •

Soft Nappa leather seats replace perforated leather

Curved-face tail lights replace square stepped lights

New engine vanity cover

Chrome bezels around instrument cluster gauges

2001    

Sport package made standard on all models

                             SPECIFICATIONS: R129 SL Models • 1989-2002

MODEL              300SL a               300SL                   SL280 a                    SL320   
YEARS             1989-1993         1990-1993               1993-2001                1993-1998   
CHASSIS           129.060              129.061               129.058, 059                129.063   
ENGINE            M103 E30            104.981                  M104 (I-6)                M104 E32   
                            I-6/12V               I-6/24V                  M112 (V-6)                  I-6/24V   
Displacement     2,860cc               2,960cc                   2,799cc                    3,199cc   
Horsepower     190@5,700          231@6,300            193/204@5,600         232@3,750   
Torque (lb-ft)    192@4,500           201@4,600             199@3,750               232@3,000   
Transmission    5-speed manual   5-speed manual    5-speed manual    5-speed auto3   
                          4-speed auto2     5-speed auto2       5-speed auto2                           
Curb Weight (lbs)       3,638              3,836                    3,880/3990               4,010   
0-60/top spd(mph) 9.5 sec/223    8.3 sec/143         9.9 sec/140            8.1 sec/149   
Total Built              12,020               8,768                  12,023                  32,223   

a. Model not offered in the United States