Introduction
The R129 is the fourth generation of the SL and is my favorite of the series. The 300SL Gullwing and 300SL roadster are beautiful, but they are a bit old for my tastes and I also don’t have pockets deep enough to buy (or maintain) them. The 113-Pagoda and 107-body SL are without doubt classics... but they don't have a lot of power and I think they are dated in many 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 a retractable hardtop. Through all my searching, 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 R230.
With later V8 models which feature the M113 engine, you also 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 Arizona, 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. Thanks for taking the time to check this out!
- Brian
Things to note when you are examining the car
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).
Click here to read more about the different special editions.
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.
A mechanics take on the R129 (by Bud Cloninger)
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.
- Bud
