Many of us occasionally see the Mercedes M-100 cars (the 1968-72 300SEL 6.3, 1977-79 450SEL 6.9, and 1963-81 600 limousines) for sale. These V-8-engined wonders were the top of the line MBs of their day, and even now continue to enjoy popularity among MB enthusiasts who appreciate their special blend of timeless elegance, Vette-eating performance and Q-ship stealth. There's something smugly satisfying when travelling down the road in a 6.9 that appears to the rest of the world, for all intents and purposes, to be a slow, lumbering 70s S-body SDL diesel !

Purchasing M-100 cars (for the purposes of this article I will henceforth focus exclusively on the 109-bodied 300SEL 6.3) is essentially similar but yet different than purchasing other 108 and 109-bodied Mercedes-Benzes. We're all familiar with the relatively easy availability, but often moderate to high cost, of parts for the W108/109/110/111/112 MBs.

Many an owner purchases $1-2000 "easy fix-it" six-cylinder 108 and 109 Benzes with the idea of putting another few thousand into the car and making a reliable long-term daily driver out of the car. In some cases this is accomplished, but in many other situations, the owner finds the time requirements, cost and sheer number of the parts and labor involved to be many times his/her original estimate of bringing the car up to a solid, drivable state.

The best advice and strategy in this case is to spend more money up front -- $5,000 and up is a good starting point -- to purchase the best, most solid W108/109 that one can get. Nearly everyone who has been through the above situation would lend the same advice to the potential Benz buyer.

With the 6.3, however, one must even approach the situation with even more caution. One joke that has long been in vogue among M-100 owners is that the 6.3 moniker is in reality a "multiplier" which must be used to calculate all licensing, registration, gasoline consumption, parts, labor and insurance costs of owning and operating the vehicle. In reality, this multiplier effect is indeed occasionally true.

When purchasing an M-100 automobile, realize up front that one is expected to pay $15-20,000 for admittance into the "club." In other words, no pay, no play. It is important to recognize that one WILL pay this amount up front, or eventually, to get the car operating as it should at a baseline level. It is a MUCH easier pill to swallow to pay the $12-15K up front, have a working car with little need for restoration, and then pay $5,000 eventually (while enjoying the car all this time) to get it up to proper operation & pristine condition.

Here are the most recent Q2 '00 values on 6.3s (from The SL Market Letter):

1969-71

• Condition #1 $46,000
• condition #2 $23,706
• condition #3 $14,246
• condition #4 $4786
• condition #5 $2800
• condition #6 $1,000

CONDITION #1 -- restored to current maximum professional standards in every area. As new. A 98+ point show car that is rarely driven.
CONDITION #2 -- Preserved originals with minor wear. Or, well-restored cars with some annual street use. 92+ point car. No trace of repairs when done.
CONDITION #3 -- Worn originals with higher mileage and repaint. Or, good amateur restorations, mixture of NOS and older components
CONDITION #4 -- Drivable, needing only minor work to be reliable, but deteriorated and incorrectly rebuilt or modified.
CONDITION #5 -- Needs complete restoration. May or may not be running, but not wrecked or stripped. Too good to part out.
CONDITION #6 -- Seriously damaged and/or deteriorated, excluding major fires. Commonly more practical for parting out. Rebuilding is unlikely.

SL MARKET letter recommends that people purchase Condition #1-3 cars. For the Condition #1-3 prices, they are "what you'll pay, later if not sooner"

Quote from an SL Market Letter article about M-100 car values:

"There is absolutely no question that the Condition 2 and 1 prices (which I quote above) are occuring on all three (6.3, 600 and 6.9) of these models. ... The significance of this is high: average prices in most categories have gone nowhere, pulled down by the mediocre cars are included in all price guides, including our own. ... Even Condition #3 purchases are marginal, because condition differences are bigger than price differences in Condition #2. Ditto for Condition #1. Only reasons to stop short of buying Condition #1 are: a) a light wallet, or b) Condition 1 cars are too good to drive."

One can see the DRAMATIC ($10,000 !!!) difference above between Condition #3 and Condition #4 6.3s. Potential owners (or eBay lurkers) are often lured by $4,000-8,000 "like-new, meticulously maintained" 6.3 cars. In reality, these are 6.3 parts cars that simply have operating drivetrains. Let's examine this further:

If one buys a $4,000 6.3, it will immediately require at least $10,000 to make a daily driver out of it. A breakdown of this $10,000 can be divided into three buckets: air suspension, miscellaneous parts, and interior and exterior cosmetics. We'll examine each of these categories further.

AIR SUSPENSION. The Golden Rule of M-100 cars is that all cars under $12-15,000 have non-working air suspension. This means that the car's complex suspension loses air pressure, causing the vehicle to sink down to the level of an East LA lowrider overnight or over the course of a day or two. While operating the vehicle pumps up the suspension temporarily, system leaks cause the car to droop down at one or both ends.

To bring a 6.3 air suspension to a known-good, up-to-spec condition, count on spending around $4,000 for parts and labor. This is for rebuilt air valves, new air bags (actually an inexpensive part), any leaking metal air lines that need replacing, and compressor maintenance (the compressor is a miniature one-cylinder engine in itself!). Labor on air suspension isn't in itself prohibitive, because the valves, compressor, airbags and lines are pretty easily accessible under the hood and under the car. However, fixing the system isn't en easy accomplishment for the novice/moderate driveway mechanic. It is a job best left to an experienced professional. That means a factory-trained Mercedes-Benz professional WHO HAS WORKED ON MB AIR SUSPENSION BEFORE WORKING ON YOUR CAR'S.

MISCELLANEOUS PARTS. Like with any used car, one must look carefully and closely for items that are worn, need replacing or are just plain dingy. Of course the usual 108/109 parts apply here, such as subframe mounts, door rubber, windshield & trunk seals, underhood rubber, oil and water cooling hoses, tie rod ends, steering box seal, wind-lace, and other "soft" parts found on the car. Again one must count on $3-4,000 to repair and replace these various soft goods on the car. After doing these steps, the car is driveable and relatively reliable. Because of their high torque, the engines and less often the transmissions generally live charmed lives, because they don't have to work nearly has hard over their lives as the smaller 6-cylinder M130 motors. This is fortunate, and in general the motors don't require significant refurbishment except for common "rot and wear" parts such as hoses, belts and mounts (which by even 6.3 standards are cheap and commonly available).

Total spent to date: $4,000 (purchase) + $4,000 (air suspension) + $3,000 (misc parts) = $11,000.

INTERIOR & EXTERIOR COSMETICS. Lastly one comes to the interior & exterior cosmetics. Typically the interiors of the M-100 cars wear pretty well, with worn driver's seats, faded interior carpets, faded paint, some body rust/rot, and often delaminated wood being the most obvious problems. Most of the interior issues many people live with or fix, with more attention being paid to the exterior of the car. Moderate resprays tend to run $3-6,000, with an additional $1-3,000 for additional interior cosmetic work needed to make the car look decent. Total spent: $11,000 + $5,000 (paint & exterior) + $2,000 (interior bits) = $18,000

Compare this conservative total (which is really required to bring a low-end car into moderately reliable and attractive condition) to the cost in the 6.3 cost table above. For that same $18K, one can purchase a pampered 2 or 2- condition 6.3 that is in every respect an order of magnitude better than a "fixed up" $4,000 M-100.

In my book this is a pretty convincing case to just pay the required amount up front, and save oneself the time, cost and mental hassle of bringing a low-end M-100 up to par.

Gerry Van Zandt