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The R129 is the fourth generation of the SL and is my favorite of the series. The 300SL Gull-wing and 300SL roadster are indeed beautiful, but they are a bit old for my tastes and I also don’t have pockets that deep. The 113-Pagoda and 107-body SL are without doubt classics… but I think they are dated in a lot of ways. I believe the 129-body SL offers a great compromise between power, modern technology, and the comfortable cruising you’d expect from an SL.

Before I jumped in and bought an R129, I looked quite a bit at the 230-body SL. I don’t like the look of the body style as much as the R129, but they do feature retractable hardtop. Through all my experience, I’ve found there are several advantages the R129 has over the R230:

• You can actually fit golf clubs in the trunk; I’ve actually managed to fit two full golf bags in there! You’d have a hard time squeezing a 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.

This guide is my attempt at helping folks who love the R129 or are interested in buying one. I've collected information from various sources and wrote most of the guide myself. Bud Cloninger, MBCA Desert Stars section President and owner of MB Motors here in Phoenix AZ, has also helped a lot by contributing content. I've tried my best to note where credit is due.

I hope you all will find this information useful. If you have any feedback, please contact me or put a comment below. Thanks for taking the time to check this out - Brian

Translations of this guide

So you finally find a car in the newspaper, online, or for sale at a dealership. Here are the most important things to keep in mind while you are examining the car.

Does the car have a wiring harness issue?

If the car is model year 1993, 1994, or 1995 more than likely there was or will be a wiring harness issue. It’s a known problem but a recall was never issued. Repairing this can cost several thousand dollars (unless you do it yourself; parts cost roughly $500 - $700). If you are considering a 1993 - 1995 model year and can’t verify if the harness was replaced, take the car to a good Mercedes-Benz mechanic. Someone that has worked with these cars a lot should be able to quickly tell and give an estimate if the harness needs replacement.

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 roll bar and helps provide a super quiet ride when you have the top down. If the car has one you’ll find it in the trunk. Pop the trunk and you should see a compartment held by 3 straps. Un-strap those and you should see the windscreen, hopefully in good shape.

Does the car have a removable hard top?

If the car you’re looking at does not have a hard top, you will have to find one that fits. The roofs for all R129s are not entirely interchangeable. Late model SLs have a much larger seal around the A-pillars and windshield surround.

Does the car have a panoramic roof?

You’ll notice the very top is black and the rest is body colored. If the car is black, you’ll probably have to jump in to notice. Regardless, you can tell the difference in the hard tops from the outside. The panoramic roof has a more round and much smoother shape to it. Having the roof from the beginning is a huge plus; Buying the roof afterwards can cost anywhere from $500 - $2500 and you may have to match the paint and interior after that. I am not positive, but I think the panoramic roof is only compatible on model year 1995+ because of the seals.

The soft top and rollover bar (by Bud Cloninger)

When you look at the car you should always work the soft top and rollover bar several times and check for hydraulic leaks at the front A pillars by the visors and at the pistons that lift the top and soft top boot. In my experience the tops that are not exercised occasionally have a better chance of leaking.
    You can tell if the soft top is original by examining it; when you look close, you should see a checkered pattern. You can also test to make sure the soft top still works well by trying to pour some water on it and see if any water makes its way through the plastic window. The canvas top comes in two pieces and just the rear with the plastic windows can be replaced if needed.

Wiring for high mounted stoplight and alternator harness (by Bud Cloninger)

Check the high mounted stop light (the 3rd brake light) for function. If it does not work there is most likely an open in the wires at the right side trunk hinge. In two cases I have found the brake lights were stuck on because of a “short” had a cured instead of an “open” at the trunk hinge wires, and it melted wires together way into the wire loom up by the drivers left foot rest.
    Also have found on early V8 cars the alternator wire harness can chafe on heat shields when the engine mounts are collapsed from age. This can lead to serious alternator and electronic control unit failures from voltage spikes and short circuits.

Does the car have any non-standard packages?

The SL600 includes should include all options standard. If the headlights aren’t Xenon, maybe they were replaced because of an accident. For other vehicles, you’ll want to see if any packages were included. There are two main packages: SL1 package which features an AMG body kit (bumper, side skirts) and 18 inch AMG alloys with sport tires. The SL2 package offers Xenon headlights and heated seats.

Is the car a special edition?

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 they have. 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), Silver Arrow Edition (2002).

Is the car an AMG model?

Inspect the car closely, because it’s easy to buy AMG badging and put it on the car, and it’s easy to buy AMG wheels. An AMG is distinguished by its hand-built engine with a distinctive serial number 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 live in Europe. Keep in mind that only 204,940 total units of the R129 SL were made so the AMG models are extremely rare and valuable. If the buyer is questionable, most likely it’s not really an AMG original.

    Now I have been dancing around a 129 car without much comment, the V12 Roadster. First off let me say that all comments are from a mechanics point of view.

    The V12 is a car that “only a mother could love”. The early 129 V12’s were very problematic from an emissions stand point (ck engine light). 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 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 it’s little brother the 104 engine it stands to reason it should also have the same oil leak, 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 remove 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 al 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 V12 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 any V12 you had better be willing to devote allot of resources into keeping it in good shape. You can now find these cars for under 10k so don’t be fooled into thinking your getting a good deal. Now remember this is from a mechanics point of view, I can only imagine the owners.

Just some random thoughts,

Bud

1994 models...

were the first to have the new designation. For example, 500 SL is now SL 500.

1996+ models...

featured minor facelifts for the car:

• V8 and V12 upgraded to 5 speed electronic transmission; previous transmission was hydraulic 4-speed
• Bumper and side panels are now body color
• Grill now only has 6 slats instead of 7
• Front fender vents updated; only 2 rounded slots, rather than 3 squared slots
• 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 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

1999+ models...

featured a second facelift occurred for models which included:

• V8 engine switch from M119 to M113
• Body color door handles
• Side mirrors in the SLK style
• Soft Nappa leather seats replace the perforated leather seats
• Tail lights with curved faces replacing the classic square stepped lights
• New engine vanity cover
• Instrument cluster now has chrome rings around each gauge
• Fiber-Optic digital audio links to the CD player instead of analog copper
• 17-inch wheels standard: Wheels are now 8.25 x 17" with 245/45ZR17 tires. Sport package is 8" (front) or 9" (rear) x 18" with 245/40 (f) and 275/35 (r) tires.

Breakdown of units produced

Total models

Model	Motor	Cylinders / Valves	Performance	Chassis	Production	# Made
SL 280	M104 E28	I6 / 24	193 hp	129.058	7/1993 - 6/1998	10,319
SL 280	M112 E28	V6 / 18	204 hp	129.059	6/1998 - 6/2001	1,704
300 SL	M103 E30	I6 / 12	190 hp	129.060	3/1989 – 6/1993	12,020
300 SL-24	M104 E30/2	I6 / 24	231 hp	129.061	3/1989 - 6/1993	26,984
SL 320	M104 E32	I6 / 24	231 hp	129.063	6/1993 – 6/1998	32,223
SL 320	M112 E32	V6 / 18	224 hp	129.064	6/1998 – 7/2001	7,070
500 SL / SL 500	M119 E50	V8 / 32	326 hp	129.066	3/1989 – 6/1998	79,827
SL 500	M113 E50	V8 / 24	306 hp	129.068	6/1998 - 7/2001	23,704
600 SL / SL 600	M120 E60	V12 / 48	394 hp	129.076	7/1992 – 5/2001	11,089
Total						204,940

AMG models

Model	Motor	Cylinders / Valves	Performance	Chassis	Production	# Made
SL 55 AMG	M113 E55	V8 / 24	354 hp	129.068	5/1999 - 7/2001	65
SL 60 AMG	M119 E60	V8 / 32	381 hp	129.067	9/1993 - 12/1995	164
SL 60 AMG	M119 E60	V8 / 32	381 hp	129.067	4/1996 - 5/1998	469
SL 70 AMG	M120 E70	V12 / 48	496 hp	129.076	1997 – 2000	150
SL 73 AMG	M297 E73	V12 / 48	525 hp	129.076	4/1999 - 5/2001	42
Total						890

Transmission Details

For the inline 6 engines

• 300SL/300SL-24/SL280: 5-speed manual gearbox, 4-speed automatic optional
• 300SL-24/SL280: 5-speed automatic optional from 1989
• SL320: 5-speed automatic standard

For the V6 engines

• SL280: 5-speed manual gearbox, 5-speed automatic optional
• SL320: 5-speed automatic standard

For the V8 / V12 engines

• 4-speed automatic standard, 5-speed automatic standard from 1996.

What models are available here in the USA?

All of the cars listed above did make it here to the US with the exception of the SL280 and the 12 valve 300 SL. Also note that starting with model year 1998, 6-cylinder models were no longer offered here in the US.

Lighting on the center AC vent

Sooner or later, the lighting in your center AC vent is going to go out. These lights specifically light up the white lines over the vent adjustment knobs and the blue push button on the vent. Instead of replacing the bulbs, the dealer suggested I replace the unit at a cost of over $1000. It took me some digging, but I found the replacement part number for the bulbs. There are two bulbs (see picture) and a third bulb if you take the unit out (this lights up the arrow on the push button for the eyeglasses case).
This part costs about $1.00 each. Here is the part number:
002 544 02 94

One reader sent in a note regarding this part... Part number has been changed to 072601012230. He also notes that this part may not fit 1990 - 1992 models.

AMG pedals

You can easily upgrade the appearance of your R129 by installing genuine AMG Pedals. I was made aware of this by BenzWorld.org R129 forum moderator Lynns. The emergency brake and brake are both essentially covers you can slip off to replace. The accelerator is easily swappable also.

These parts cost around $45.00. Here are the part numbers for all three pedals:
A 170 290 01 82
A 230 430 00 84 64
A 170 300 00 04

STAR Classic Service Manual Library

When in doubt, you can order the official R129 STAR Classic Service Manual Library on DVD. You’ll need a Windows machine to browse the content. When you pop the DVD in, you can see step-by-step instructions for removing or replacing parts. For the folks that aren’t scared of buying genuine parts and doing service themselves, this is a must have. This DVD is good for US models 300, 320, 500, and 600. To order, call MBUSA at 1 (800) 367-6372.

This cost approximately $88.00. The part number is:
P-2700-129-07

	Noakes, Andrew. (2004). Mercedes SL Series: The Complete Story     (pp125-148). Location : The Crowood Press Click here for more details
	Ries, Hermann (2009, Fall). Simply beautiful     Mercedes-Benz Classic, 76 - 79. Click here for more details
	Mercedes-Benz R129 SL-Club e.V. : TECHNISCHE DATEN Click here for more details