The Mercedes-Benz R129 automobiles were produced from 1989 through 2002. They were sold under the SL-Class model names. The R129 replaced the R107 SL-Class in 1989 and was in its turn replaced by the R230 in 2003 (US).
Designed in 1984, the R129 was based on the shortened floorpan of the Mercedes-Benz W124 and featured many innovative details for the time, for instance electronically controlled damping (optional) and a hidden, automatically extending roll-over bar. The R107's rather dated rear diagonal swing axle gave way to a modern multi-link axle. The number of standard features was high, with electric action for the windows, mirrors, seats and convertible top.
1994 models were the first to have the new designation. For example, 500 SL is now SL 500. Starting in 1994, Mercedes-Benz offered special SL models from time to time, such as the Mille Miglia edition cars of 1994 or the SL edition of 2000.
1995 had minor updates for the car:
- Odometer switched from mechanical to electronic
- Option for portable cell phone with voice activated dialing
- Clear front turn signal indicators for US SPEC models
- Bose stereo now standard, rear speakers and subwoofer
1996+ models featured minor facelifts for the car:
- Front fender vents updated; only 2 rounded slots, rather than 3 squared slots
- Bumpers are now body color
- V8 and V12 upgraded to 5 speed electronic transmission; previous transmission was hydraulic 4-speed
- Xenon HID headlamps standard on SL600, optional on SL500
- Addition of side airbags
1997 cars were the first year to have an option of the panoramic roof. Also newly available:
- A new front-seat occupant-detection sensor could deactivate the right-side airbag when it determined that the passenger seat held less than 26 pounds
- "Sport" package became an option
- Automatic rain-sensing windshield wipers standard
- Three-way programmable garage door opener "HomeLink" transmitters built into the rear-view mirror
- Replaced the earlier climate control panel with one with a much larger LCD
- Remote control uses dual infrared (IR) and radio (RF) control
A second facelift occurred for models 1999+ which featured:
- V8 engine switch from M119 to M113
- Soft Nappa leather seats replace the perforated leather seats
- Body color door handles
- Tail lights with curved faces replacing the classic square stepped lights
- 17-inch wheels standard: Wheels are now 8.25 x 17" with 245/45ZR17 tires. Sport package is 8" (front) and 9" (rear) x 18" with 245/40 and 275/35 tires respectively.
- Fiber-Optic digital audio links to the CD player instead of analog copper
- One-touch starting- called "Tip-start". Once the key is turned, the engine cranks on its own until it catches and starts.
- Instrument cluster now has silver rings around each gauge
- Oil pressure gauge replaced by oil temperature
- Different engine vanity cover
- Removed the automatic lock on the left rear storage compartment which houses the Bose subwoofer
Initially, there were three different engines available,
- 300 SL with a M103 3.0 L 12-valve SOHC L6 (190 PS (140 kW; 190 hp) at 5700 rpm),
- 300 SL-24 with a M104 3.0 L 24-valve DOHC L6 (231 PS (170 kW; 228 hp) at 6300 rpm),
- 500 SL with a M119 5.0 L 32-valve DOHC V8 (326 PS (240 kW; 322 hp) at 5500 rpm),
and joined in July, 1992 by the
- 600 SL with a M120 6.0 L 48-valve DOHC V12 (389 hp/290 kW) @ 5200 rpm).
There was a choice of 5-speed manual or 4-speed automatic for the six-cylinder cars; the V8 and V12 could only be ordered with an automatic gearbox.
In Autumn 1993 Mercedes-Benz rearranged names and models. Also, the 300 SL was replaced by:
- SL 280 with a M104 2.8 L 24-valve DOHC L6 (197 hp(145 kW) at 5500 rpm)
- SL 320 with a M104 3.2 L 24-valve DOHC L6 (220 hp (161 kW) at 5500 rpm)
Only the 280 was available with a manual gearbox. SL 500 and 600 continued with their respective engines.
A second facelift, introduced in late 1998, comprised new external mirrors, 17" wheels and new bumpers. Also new were the engines,
- SL 280 with a M112 2.8 L 18-valve SOHC V6 (204 PS (150 kW; 201 hp) at 5700 rpm),
- SL 320 with a M112 3.2 L 18-valve SOHC V6 (224 PS (165 kW; 221 hp) at 5600 rpm)
- SL 500 (306 PS (225 kW; 302 hp) at 5600 rpm) — full throttle enrichment removed.
The V12 engine remained unchanged.