The Star® Journal

Article: Pierre Hedary & Gary Anderson
Contributions: Daniel Stahl & Richard Simonds
Images: Daimler Archives

Few luxury sedans survive long enough to become classics; fewer still are actually affordable by the average enthusiast. The W126-chassis Mercedes-Benz, produced for a stunning 12 years from 1979 to 1991 and sold in the United States from 1981, is a strong contrast in both respects. The W126 was, according to many experts and marque aficionados, the best S-Class Mercedes-Benz ever made.

Examples that received the care and respect they deserved when new are still being driven today. In fact, enough of them have survived in excellent condition that they are not only affordable as entry-level classics, but are even good values for the person who wants a daily driver that is luxurious, stylish and easy to work on for the price of the cheapest new econobox.

Background

In the years following the 1973 gasoline crisis and the furor arising from Ralph Nader's book Unsafe at Any Speed, automotive manufacturers were challenged to meet increasingly stringent safety requirements, as well as higher standards of fuel efficiency. Mercedes-Benz had been testing a gasoline-powered aluminum-block V-8 and a high output [for the time] turbocharged diesel engine, and was already selling its 2.8-liter twin-cam six in the W116 sedan, introduced in 1973. The W116 car was a well-made car, but the climate control, U.S. bumpers, emissions systems, and other components needed further development to meet world requirements; a completely new design was required to fully address these outstanding issues.

Mercedes-Benz complied: In 1979, the first new W126 Sonder Klasse (special class) models – the 380SE, 500SE and 280S – were delivered to showrooms in Europe. Two years later, the company introduced the 380SEL, the long-wheelbase version of the 380SE, and the 300SD diesel-engine version of the W126, to customers in the United States.

The 300SD was an instant hit. Sales took off and the big sedan won Motor Trend's Car of the Year Award, a first for such a large vehicle. Extremely well-made, nicely-optioned 300SDs – often pictured in the light ivory color that graced Mercedes-Benz sales brochures – are still a common sight on today's roads.

The long-wheelbase, gasoline-powered 380SEL did not fare so well. The V-8 produced an anemic 155 horsepower. As smooth as the engine was, timing chain problems were its Achilles' heel, and Mercedes-Benz technicians were soon plagued with complicated and expensive chain replacements. The stylish but still mechanically challenged 380SEC coupe joined the lineup for model year 1982.

In terms of the gasoline-powered cars, many owners went further afield. The thriving gray market captivated the imagination of many Mercedes-Benz customers, and private dealers began bringing high-performance European W126 cars into the country by the dozens, federalizing and reselling them to eager clients. When companies like AMG, Brabus, Schulz and others joined in the customization and performance party, things got even better.

In 1985, ABS became standard on the W126, heralding a new era of performance and safety. In that same year, the U.S. lineup included the 500SEL, 380SE and 300SD. These models were replaced by the more powerful 420SEL and 560SEL/SEC in 1986. Handsome and refined, one of these new V-8 flagships became the luxury automobile to own if you wanted a big sedan.

On the other hand, the 300SDL with the OM603 turbodiesel that replaced the 300SD in 1986 suffered at the start with cylinder head issues. Thankfully Mercedes-Benz updated the heads with improved versions, but the model was still withdrawn two years later.

Meanwhile, standard airbags and automatic seatbelt tensioners were added to protect drivers of these increasingly fast sedans. In 1988, the 300SE and 300SEL joined the line-up; in 1989, interiors, cooling systems and exterior panels were updated. In 1990, the 350SD/SDL joined the lineup, and the last W126 cars were sold in the United States during the closing months of 1991.

The number of these cars still on the road attests to their workmanship and reliability. The quality of the W126 range is so high that many perfect examples still exist. Few can dispute the charm, elegance and practicality these cars still convey.

Reasons to Buy

• Safety, reliability, and comfort made them excellent for daily driving or long-trip touring.
• Heating and a/c systems were significantly improved and made a W126 comfortable and usable all year around.
• Engines (both gasoline and diesel) and drive trains were increasingly robust and long-lived with proper maintenance.
• Interiors (especially M-B Tex) are durable and easy to clean.
• Values are exceptional at this point in their life cycle (27-36 years old) but are expected to begin appreciating for well-cared-for, preservation-class vehicles.
• Diesels get mileage comparable with new Mercedes-Benz diesels (high 20s to low 30s on the road).
• The W126 is still contemporary looking and offers comfort for passengers, plenty of luggage space and excellent visibility.
  
  

Reasons Not to Buy

• Many examples for sale suffer from lack of maintenance, which may not be readily apparent in a casual inspection.
• Genuine OEM Mercedes-Benz parts are relatively expensive and may not always have been used in servicing.
• Aluminum-block engines were vulnerable to overheating, especially if coolant systems were not carefully maintained.
• Gasoline-engine models are not as fuel efficient as diesels, especially compared with modern cars.
• In spite of excellent rust protection, the elaborate design of the body makes it vulnerable to rust, which is easily camouflaged and expensive to repair.
  
  

Checkpoints

• Early 380SE/SELs should be checked for timing-chain updates, with chain guides, chains and tensioners replaced.
• Excessive oil consumption, especially on gasoline engines, may mean worn valve guides or head gaskets; this is an indication of an engine in need of rebuilding.
• 350SD/SDL engines are particularly prone to damage from overheating, and to rod failure; check maintenance records for proof that the engine has been recently replaced or budget for engine replacement.
• Bio-diesel or vegetable oil conversions should be avoided because the lubricity and cetane rating of these fuels can lead to catastrophic engine failure.
• Plastic radiators are prone to leakage and cracking, which may also lead to overheating and engine wear.
• Front-suspension ball joints and bushings are prone to wear or failure and require specialized tools to replace.
• A/C compressors should be checked for effective operation, ensuring cold air is produced from center dashboard vents; if necessary, replace with a new Behr unit.
• HVAC defroster vents should close completely when a/c is operated, otherwise a/c actuators may need replacement. A/C repair is complicated because of dashboard design.
• Seats that sag indicate broken springs and worn-out horsehair pads; torn or cracked leather or MB-Tex may need replacement.
• Dashboards with cracked vinyl, worn leather and discolored or damaged wood trim are likely to be expensive to restore.
• Rear-window glass is prone to delamination, leading to rust in rear shroud sheet-metal panel.
• Back-door vent windows operate by sliding-jaw gear. A replacement part is made; replacement is complex and costly.
• Airbags should be replaced every 10 years on all cars; check if this was done by an authorized Mercedes-Benz Center.
  
  

Buying tips

If you are a first-time W126 buyer, look for a 300SD. These cars are known for clocking over half a million miles with no real problems. They are easy to start in all conditions, are quiet and quite powerful, and good examples are easily found. While the model was known for cylinder head issues, most still-running examples have been sorted, and the result is impressive – a comfortable and quick diesel sedan that gets 28 mpg or better, with little noise and no turbo lag.

The successor 350SD was known for connecting rods unable to handle the engine's torque; many units had to be rebuilt under warranty. Many machinists also agree that these engines would leak oil through their valve guides, and on cold starts, the fluid pressure on top of the piston could damage the connecting rods. Poor fuel quality, lackluster maintenance by some owners, and stop-and-go traffic all conspired to damage these engines, marring their reputation. However, these can be fantastic cars when their engines are "right."

The best gasoline-engine model is the 1988 300SE/SEL with its bulletproof easy-to-service, I-6 M103 engine. It's not as fast as the V-8s, but has better balanced performance and is easy to service. A detailed prepurchase inspection, with partial disassembly of the engine to check for timing-chain servicing, head-gasket condition and possible valve wear is money well spent unless you've budgeted for a rebuilt replacement engine. Alternatively, a well-sorted 420SEL or 560SEL is a hoot to drive.

In Europe, a 500SEL was available with four-wheel hydraulic suspension. These gray-market cars are not for the faint of wallet, but handling is beyond anything else Mercedes built at the time. The option was offered on some 560SELs, but this model is difficult to find.

When reconditioning interiors, use Mercedes-Benz horsehair pads and ensure that the grain of the leather is correct. Many suppliers are selling incorrect rough-grain leather, which is also less attractive and uncomfortable. Most interior trim is still available from Mercedes-Benz or the leading interior-trim suppliers, though it will be costly.

While gray-market cars were once frowned upon, these models have now come into their own. While their velour interiors are hard to get repaired, the high-horsepower Euro engines with manual gearboxes are exciting to own. AMG did some wonderful things with bodies and power plants, making the W126 its flagship, and attaching twin-cam heads to the V-8 engines. In states such as California, make sure your car can pass the emissions test before you buy it.

The best W126 cars are still under $15,000, though AMG versions can fetch as much as $50,000. As they become more collectable, their value will only rise. These cars pay off in the long term, as many satisfied owners can attest. Even with the cost of service, these cars deliver more than you have to put into them, and with reasonable care are likely to continue to do so for decades to come.