Buyers Guide - 1990-2002 R129 SL500/SL600 Roadsters

The SL roadsters on the R129 chassis, including the 300SL, 500SL, 600SL, SL500, and SL600, are the fourth generation of the SL, and are on their way to becoming modern classics.

The R129 SL Roadsters, 1990-2002
Proper Successors to the Classic Roadsters
A brief buyer's guide to the SLs from 1990 through 2002

Article and photography by Brian Clifton
With Contributions by Bud Cloninger and Pierre Hedary

The SL roadsters on the R129 chassis, including the 300SL, 500SL, 600SL, SL500, and SL600, are the fourth generation of the SL, and are on their way to becoming modern classics. Considering the alternatives in today's market, with the R129, you get a lot of car for your money. The 300SL Gullwing and 300SL Roadster are indeed beautiful, but they can be extremely expensive. The 190SL is beautiful but pricey, and it doesn't offer stellar performance.  Even the the W113 Pagodas and R107 "Panzerwagens" are without doubt classics,  but they are dated in many ways. The 129-body SL offers a great combination of style, power, modern technology, and the comfortable cruising one would expect from an SL. 

Background

The previous SL, the R107, was in production from 1971 until 1989, the longest production for any chassis type, with the exception of the G-Class.  During those years, the car became dated in many ways.  Newer features such as airbags had to be retrofitted into the chassis. Other cars started to integrate computers.  The 107s are without a doubt elegant, but the automobile industry came a long way in those 18 years.

The new R129 for model year 1990 premiered at the Geneva Motor Show in early 1989. The design team behind the styling of this new convertible was led by the great Bruno Sacco, who also was behind the design of the W126 S-Class and the W201 "Baby Benz" C-Class.  Besides having a much more modern visual style than the R107, the 129 was designed with innovative safety features.  These include the new roll bar which deployed in one-third of a second; an extremely strong chassis with a floorpan based on the W124; ABS braking; and seat belts that actually fit the height of the occupants.

The roll bar was a significant new safety feature for convertibles. It normally sits flush with the tonneau cover but pops up to a protective height in one-third of a second when a sensor detects an imminent rollover. The roll bar can be raised and lowered using a button on the console.

One of the main features of the car is the automatic softtop.  When the hardtop is removed, the soft top underneath can be opened or closed at the push of a button. Start to finish, it does this in roughly 30 seconds. 

The first R129s were introduced with two engines, an inline 6-cylinder engine in the 300SL and a V-8 in the 500SL.

As the production continued, the R129 continued to receive more improvements and features. The 3-liter engine was replaced with a more fuel-efficient 3.2-liter in MY1994, but then in 1998, the 6-cylinder engine was withdrawn from the U.S. market. The original 5-liter 32-valve engine in the 500SL introduced in 1989 was replaced by a more fuel-efficient, but slight lower powered 24-valve V-8 with the same displacement in 1998 and that engine continued to be used until the R129 was replaced in 2002. V-12 models, with engines first used in the 600SEL in 1992, were offered starting with model year 1993.

After 1995, the SLs were equipped as standard with the Electronic Stability Program (ESP). Overall, the R129 SL has a great combination of safety, comfort, power and beauty.

Reasons to buy an R129

• Great value in today's market. These are outstanding cars.
• With airbags and an extendible roll bar, these cars are extremely safe convertibles.
• The removable hardtop is standard.
• The trunk is relatively spacious compared to other convertibles.
• Cars without ADS or ADS II have reliable suspensions.
• Parts are readibly available and components are generally simple to repair.

Reasons not to buy an R129

• With the roll bar, the R129s only hold two people; the back area cannot fit anyone safely.
• Limited trunk space compared to a sedan.
• The removable hardtop requires two people to remove and install, or a special garage hoist.
• Model years 1993-1995 can suffer from wiring harness issues that are expensive to fix.
• SL600 with Adaptive Damping System (ADS) or ADS II suspension can be extremely expensive to maintain.
• If the car has staggered wheels, tires  can be expensive.  A set of Michelin PS2s costs approximately $1,600.

Checkpoints

1. Potential mechanical issues? Wiring harnesses were a known problem area in model years 1993-1995, but a recall was never issued. Repairs can cost several thousand dollars (unless you do it yourself; parts cost roughly $500-$700). If you can't verify whether the harness was replaced on one of these models, take the car to a good Mercedes-Benz mechanic to determine if the harness needs replacement and give you an estimate. Other components to have checked include head gaskets on the early  300SLs with the M104 engine. On 500s and 600s with the 5-speed automatics, especialliy if the car was driven hard, the 5th gear overdrive was prone to problems that can be expensive to fix.The instrument clusters on earlier models, which have a mechanical odometer, are more prone to failure.  Be sure to check this and, if possible, verify mileage by looking at records or doing a carfax.Also, be careful about models that feature Acceleration Slip Regulation (ASR); if a failure happens it can be hard to diagnose and expensive to repair.
2. Does the car have a wind-protection screen? Starting with model year 1993, the wind-protection screen (also called a "draught-stop") is standard equipment. The windscreen snaps onto the rollover bar and helps provide a very quiet ride when the top is down. If the car has one, you'll find it in the trunk in a compartment held by three straps. Unstrap those to find the windscreen; hopefully it will be in good shape.
3. Does the car have a removable hardtop? If the car you're looking at does not have a hardtop, you will have to find one that fits. Hardtops for all R129s are not entirely interchangeable. Late-model SLs have a much larger seal around the A-pillars and windshield surround.
4. Does the car have a panoramic hardtop roof? you can spot a panoramic hardtop from the outside, since they're black and the pano roof has a rounder and smoother shape; the difference is obvious on the inside. Having the panoramic roof with the car you buy is a huge plus; buying one in today's market can cost anywhere from $500 to $2500 and you may have to match the paint and interior after that. I believe the panoramic roof is only compatible on model years 1995 and after because of the seals.
5. Do the soft top and rollover bar work properly? Always work the soft top and rollover bar several times to check for hydraulic leaks at the front A-pillars by the visors and at the pistons that lift the top and soft-top boot. Leaks are more likely to occur on tops that haven't been exercised often. Check the soft top; original tops will have a checkered pattern on the inside. Test to make sure the soft top is still waterproof by pouring water and see if any water leaks through the plastic window. The canvas top comes in two pieces and just the rear with the plastic windows can be replaced if needed.
6. Is the car a special edition or desirable model? There are several different special editions of the 129-body SL. These could significantly affect the long-term value of the car. It's possible the owner doesn't know what he or she has. Here is a list of the editions to keep an eye out for: Mille Miglia Edition, Designo Edition, 40th Anniversary Roadster Edition (1997), Special Edition (1998), Final Edition (2000), SL Edition (2000), and Silver Arrow Edition (2002). In 1990 and 1991, a few 300SLs were sold in the States with a 5-speed manual transmission. They are rare but a lot of fun.
7. Is the car an AMG model? Inspect the car closely, because it's easy to buy AMG badging and AMG wheels and put them on the car. An AMG is distinguished by its hand-built engine with a distinctive serial number and a badge on the engine signed by the builder. There are only four types of AMG-modified SLs, and they are rare:  the SL55 (65 units made), the SL60 (633 units made), the SL70 (150 units made), and the SL73 (42 units made). Most of these cars are still in Europe. Keep in mind that only 204,940 total units of the R129 SL were made in all so the AMG models are extremely rare and valuable.  If the buyer is questionable, most likely the car is not really an AMG original.

Chronology

1990 models...

• Premiered at the Geneva Motor Show in spring 1989    

1994 models...

• Were the first to have the new designation (e.g., 500 SL is now SL500).

1996+ models...

• Featured facelifts for the car:
• V8 and V12 upgraded to 5 speed electronic transmission; previous transmission was 4-speed.
• Bumper and side panels are now body color.
• Grill now only has 6 slats instead of 7.
• Front fender vents updated; two rounded slots instead of three squared slots (behind front wheels).
• Panoramic roof is now an option.
• Xenon HID headlamps standard on SL600, optional on SL500.
• Clear front turn signal indicators.
• Addition of side airbags.

1997+ models...

• Featured a new sensor to deactivate the passenger airbag when it determined that the passenger seat held less than 26 pounds (for baby carrier).  Also had a switch for disabling manually.
• "Sport" package became an option.
• Automatic rain-sensing windshield wipers standard.
• Programmable garage door opener "HomeLink" transmitter built into rearview mirror.
• Earlier climate control panel replaced with new larger LCD control panel.

1999+ models

• Featured a second styling facelift.
• V-8 engine switched from M119 to M113.
• Body-color door handles.
• Side mirrors more rounded, similar to the SLK.
• Soft Nappa leather seats replaced perforated leather seats.
• Tail lights with curved faces replaced square stepped lights.
• New engine vanity cover.
• Chrome bezels around instrument cluster gauges.

2001/2002 models

• Sport package made standard on all models.

Value Estimates

Values based on NADA Classic, Collectible, Exotic, and Muscle Car Appraisal Guide, Jan-Apr 2010 and Hagerty's Cars That Matter.

Low estimates are for cars that can be driven safely but may have problems too expensive to fix. Medium values are for cars that could win local car shows. High values are for exceptional cars that are rarely driven.

R129 or R230? by Brian Clifton

Before I jumped in and bought my 2001 SL500, I also looked at the 230-body SL that replaced the R129. I think the R129 is more attractive than the R230, but the newer model does feature a retractable hardtop.

However, since buying the R129, I've found there are several advantages of the R129 over the R230:

• You can actually fit golf clubs in the trunk; I've managed to fit two full golf bags in there! You'd have a hard time squeezing a small cooler into an R230.
• The panoramic roof option on the 129-body is amazing; it offers ridiculously large views of the sky, much bigger than the panoramic roof on the 230.
• With later V8 models which feature the M113 engine, you have a lot of supercharging options. It's essentially the same engine as what's in the R230 until the SL550 came out for model year 2007.
• Newer R230 cars feature Active Body Control (ABC) suspension which is superior to ADS, but can be extremely expensive to repair or maintain.

A Mechanic's Take on the SL600 by Bud Cloninger

The SL600 V-12 is a car that "only a mother could love." The early R129 V-12s were very problematic from an emissions standpoint (with a check engine light that's almost always on). These cars were a never-ending source of work for my shop. Not to say I made any money (because I didn't), but they sure kept me busy! From wire harness problems to oil leaks, it was just a bad design. Now don't get me wrong, from the driver's seat, this is one of the most awesome cars in the world... when all is right. The feeling of acceleration from 30 mph to 90 mph is the same as from 90 mph to 140 mph! This car pulls hard though-out any speed range and the 129 chassis handles it well.

Now I will mention just a few of the problems this car will have. Oil leaks are a problem. Because the 120 engine shares the same right-bank cylinder-head configuration with its little brother, the 104 engine, it stands to reason it should also have the same oil leak, from the front cover. After a while, if left unattended, it will soak the right side of the engine, ruining the alternator and any coolant or air hoses in the vicinity. The intake manifold will have to be removed to get to the valve cover gaskets to dislodge the front cylinder head cover. Updated intake gasket spacers will be needed along with just about every rubber air or crankcase vent hose and all vacuum hoses. Oh, and did I mention that you have to disconnect the engine wire harness from all the sensors and injectors? Wow, look at all those cracked wires. Now that's just one oil leak. I normally refer to the check-engine light as "my friend," but on the 1992 though 1995 V-12, it is my worst enemy. From plugged EGR ports in the intake manifold to carbon-fouled air-injection ports in the cylinder head, there is always a place to start and never a place to end. If you are thinking of buying a V-12, you had better be willing to devote a lot of resources into keeping it in good shape. You can now find these cars for under $10,000, so don't be fooled to think you're getting a good deal. Remember, these opinions are from a mechanic's point of view; the actual owners might agree or disagree.

References

Mercedes SL Series: The Complete Story (pages 125-148). Noakes, Andrew. Crowood Press. 2004. ISBN 1-86126-673-1

 "Simply Beautiful" (pages 76-79) by Ries, Hermann.  Mercedes-Benz Classic magazine, 03 2009. ISSN 1610 8043

Clubs: Mercedes-Benz R129 SL-Club e.V.   www.r129sl-club.de

From The Star

The Star published many articles reviewing the R129s when they were new, which may be good references for the person considering buying an R129.

• "1990 300SL & 500SL" by Frank Barrett, Jul/Aug 1989, page 22.
• "600SL Leads 1993 Models" by Frank Barrett, Nov/Dec 1992, page 46.
• "Truly Grand Tourers: The New 500SEC, 600SEC & 600SL" by Frank Barrett, Jan/Feb 1993, page 34.
• "Electronic Stability Program Offers Extra Sideslip Protection" by Frank Barrett, May/Jun 1995, page 40.
• "Driving 40 Years of Big SLs, Part I" by Ian Fraser, Mar/Apr 1996, page 56.
• "Driving 40 Years of Big SLs, Part II" by Ian Fraser, May/Jun 1996, page 48.
• "Factory News: 40th Anniversary SL" by unknown, May/Jun 1997, page 36.
• "SL600 Almost Wins the One Lap of America" by Jim McCraw, Jul/Aug 2000, page 42.

On the Market

Here are some real-world ads for R129s on the market at the time this article was written in July 2010, as examples of availability and prices.

1997 SL500 $18,995 Convertible Imperial Red/parchment. 67,000 miles. Many options including Panoramic Hard Top, Sport Package, Xenons etc. Staggered 18-inch wheels and tires. Newer tires & battery. Includes original books, manuals and 101k window sticker. Very good condition. David Doherty; (716) 688-0540; ddoherty1966@aol.com (NY). From The Star, May-June 2010.

1992 300SL $12,995: Rare, classic coupe! Excellent condition, low-mileage 98,000, well-kept immaculate, siliver with tan interior, 6-cylinder engine - best engine made for this model - includes hard and soft tops like new. Car has new tires. From MBCA Seattle Section Silver Star May-June 2010.

1993 600SL $29,999 Convertible White /Blue. Super nice car with only 21,000 well cared for miles, all original, and working perfectly. (except stereo upgraded to Alpine) Includes MB cover, and books. No wrecks or damage ever. A real time capsule car, sure to appreciate quickly. Located near Pittsburgh. Joseph Cousins; (724) 525-7055; visemeister1@gmail.com (PA). From The Star, May-June 2010.

1998 SL500 Convertible $17,500 Brilliant Silver/Black 98,000 miles. Original Sport Package with 18-inch AMG wheels and bodywork. Preferred model year with 4-speed automatic and higher output engine. Multiple MBCA section show awards. European lights (originals included). Garage kept. Immaculate Hardtop with carrier/cart and dust cover. Perfect rear windscreen. All books/manuals and records. New battery and soft top windows. Joe Lofaro: (201) 920-5222; JRLMD@aol.com; phone preferred. (NJ) From The Star, July-August 2010.

By the Numbers

1. Not offered in United States.
2. 5-speed auto standard from 1996.