Buyers Guide 1985-1995 W124 Lineup

1985-1995 W124 Lineup
A Buyers Guide to the mid-sized chassis series that became the E-Class

By Pierre Hedary and Gary Anderson
Contributions Albrecht Stachel and Richard Simonds
Photographs Daimler Archives

Breaking from typical product development practices, the W124s – the first models in the Mercedes lineup to carry the E-Class designation – were actually styled and engineered following the designs of the compact W201 class introduced a year earlier, though they incorporated the safety innovations introduced on the W126 S-Class models introduced four years earlier. Testimony to their quality and class-leading attributes, the W124s continued in production for 11 years, upgraded three times before Mercedes-Benz saw the need to introduce a new mid-sized chassis.

During their lifetime, the W124s were produced in sedan, coupe, cabriolet and station wagon body styles, and from almost the beginning, were available with 6- and 8-cylinder gasoline engines and 6-cylinder diesel engines, with optional four-wheel drive in the sedans and wagons. The consequence is that there are lots of these cars on the market for buyers to choose from, ranging from reliable daily drivers at reasonable prices to interesting collectible models that can be shown with pride and driven with enjoyment today.

The W124 lineup included a practical station wagon by 1987 and a stylish coupe a year later. After the W124s, the E-Class lineup always included sedan, coupe, cabriolet, and station wagon.

Background

Over its long lifetime, the W124 became the centerpiece of the new Mercedes-Benz marketing strategy, built around a compact, midsize, or full-size chassis. Drawing on developments from already existing models, suspension and chassis engineers were able to design a highly reliable car with great handling, a comfortable interior, and competent performance. Having accomplished this, one might say that the company simply said to itself, “Why bother to change?”

Nevertheless, exterior styling and interior appointments were updated twice, and the engines were upgraded for better performance. But the major strategic development was to add a station wagon, coupe, and four-seat cabriolet to the lineup, broadening the brand’s market appeal.

Faulty head gaskets are a common mechanical flaw in these otherwise reliable cars. However, the only real design flaw in these solid citizens is the first-generation Automatic Climate Control air-conditioning system, which is expensive to fix because of its vacuum-operating duct controls, even by a mechanic with experience on this generation of HVAC systems. The evaporator is also a frequent candidate for replacement.

Reasons to Buy

• The 124s were the safest Mercedes-Benz cars built when new, with the last cars featuring dual airbags, traction control and an automatic roll bar on the cabriolet.
• This model is notable for being much more rust-free than previous or later models, reducing the risk of buying badly.
• The 2.6- and 3-liter gasoline 6-cylinder engines are simple and robust, and DIY maintenance is very easy.
• Bosch KE-injection systems are reliable, easy to service and usually easy to diagnose.
• Interiors, bodies and other cosmetic parts are very durable.
• Climate control systems are realistic and useful, even in hot climates.
• Handling is excellent, and numerous factory bolt-on parts can make it better.
• Diesel models attain real fuel economy [low 30 mpg is typical for the 300D, 300D 2.5 and E300 diesel].
• The V-8 models – 400E, 500E, E420 and E500 – offer exciting performance.
• If you like gadgets, 124s had some of the most complete standard equipment lists available at the time, including driver airbag, ABS, sunroof, and an option list that came to include automatic locking differential, orthopedic seats, ASR and some other neat items.
• Manual transmissions were available for model years 1986 and 1987 on the 260E and 300E. If you desire a midsize Mercedes with a gasoline engine and a manual gearbox, this was the only one available as a U.S. model [115s, 123s and 210s never had it in the states].
• Power output, even on the diesels, is excellent.
• No valve adjustments are needed on any of these cars, eliminating the need for overnight parking at your mechanic’s shop.
• Build quality is [mostly] in the classic Mercedes tradition. All of these cars can easily reach 500K miles with careful service.

Reasons Not to Buy

• All the 6-cylinder gas cars, from the 260E and 300E to the E320, had valve guide and head gasket issues. These can be expensive to replace.
• 1987 300Ds tend to have cylinder head issues. The 300D 2.5 and E300D are susceptible to similar problems if abused. Problems can be expensive to fix and few technicians have the needed experience.
• Air conditioning systems in this generation were problematic because of the adoption of automatic climate-control mechanisms.
• Some simple service items, such as the water pump and serpentine belt tensioner, are hard to access and require a lot of effort to replace.
• On post-1993 gas and diesel models, wiring harnesses were biodegradable and can fail, leading to expensive electrical issues, including ECU failures. Expect to replace the wiring harness if it hasn’t already been performed.
• Some areas of build quality, such as the door panels, window regulators, AC system, etc., are not nearly as robust as those on older M-Bs.
• The electronic systems of these cars is primitive. When a major issue does arise, it can be tricky to locate and diagnose.
• All those lovely bits that make these cars handle so nicely wear out quickly. Plan to spend money replacing ball joints, shocks, struts and rear spindle bushings every 60,000 to 80,000 miles.
• Many of these cars have been run into the ground. There are plenty of nicely presented examples with serious mechanical issues.
• V-8 cars are difficult to work on because of limited space under the hood.
• Disassembly and reassembly on interior items is a fine art. Plastic pieces tend to fall apart after 20 years or so.
• These cars don’t have the style that the 123 series and earlier models had. While this suits some, the 124 will never be a show-stopper like its older siblings.

Mercedes’s first four-seat cabriolet in 20 years, the E320 was attractive and comfortable, and is among the most valuable of W124s.

Checkpoints for All Models

All of the various W124 models, both gasoline and diesel, need to be checked for the following potential issues:

• The air conditioning system is a concern. Check all modes of operation – actuators are difficult to replace (see The Star, July-August 2012, p. 58-59). If the coolant reservoir is empty, or needs frequent topping, then the evaporator might be ready to fail. Replacing or repairing it will be expensive.
• Suspension components, especially the lower ball joints, require a special press to replace; with the press, the job can be accomplished in less than three hours. Front struts and strut mounts were a new innovation. Check that Mercedes-approved brands, such as Bilstein or Boge, were used for replacement. Rear axle spindle bushings usually need replacement, an expensive job without the Baum Tools pressing tool, and this job is expensive. Rear shocks are rarely replaced even when worn, but replacements aren’t expensive or difficult to install.
• The 500E and all wagon variants use the good-old self-leveling suspension, so accumulators should be assessed and replaced if the ride is bouncy.
• On the E320 cabrio, operation of the power top can be a problem. Hydraulic elements for the power top can develop leaks and the top may have synchronization issues. Replacing the top actuators costs approximately $2,000, and is best done by a dealer or an independent shop that has done this job before.
• Motor mounts should be checked on all models. The V-8 cars seem to need them the most, and they are not fun to replace.
• All functions of the automatic climate control, particularly the operation of the center vents, are difficult to access. Cycle through all functions of the climate control.
• Functioning of the sunroof. Also check for water leakage.
• Rear sub-frame attachment points on early cars are susceptible to cracking.
• Jack points, sunroof trays, battery trays and front fenders should be checked for rust. On later cars, inspect the area around the lower-body side molding, as this is an ideal moisture trap.
• The windshield wiper on the 124 has a plastic gear that fails, leading to irritating wiper problems. LLC makes an odometer gear that can be used for replacement, but complete wiper assembly prices are quite high.
• Interior bits – door panels, headliners, B-pillar covers and dashboards – should be checked. These items were not made very well when new; clips fall off the door panels, headliners fall, B-pillar moldings shed their vinyl covers, and dashboards crack.
• Rear window regulators are poorly built and tend to fail every 10-15 years.

Checkpoints for Gasoline Engines

• Leaking head gaskets on all 6-cylinder cars; look for oil in the coolant or seeping from the head gasket, and combustion gases in the coolant.
• Engine wiring harness on 1993-1995 models, including the V-8 models, which were deliberately designed to be biodegradable.
• On cars with more than 75,000 miles, an assessment of oil consumption needs to be conducted. A valve job may be required if it is excessive.
• Receipts that show the water pump, belt tensioner and/or radiator have been replaced – these are all items that last approximately 80,000 to 100,000 miles. Replacing these items can easily cost up to $1,500.
• The front crankshaft seal on all gas models. An update for this seal is available to cure oil leaks.
• Reverse gear on V-8 cars and the E320. The more powerful engines in these cars tend to put a heavy load on the reverse clutch pack in the 722-transmission.
• On the 300E with a 5-speed manual transmission, make sure that second and fifth gears do not have any engagement issues.
• On all models, be sure the cooling system is up to par on hot days with the AC on – these are expensive to repair.

Checkpoints for Diesel Engines

• On the 1987 300D and 300TD, look for signs of cylinder head failure. These include overheating, combustion gases in the coolant, and odd coolant loss that does not coincide with an external leak.
• On the 1987 300D, 300D 2.5 turbo and E300, spray around the injectors with soapy water with the engine running. The presence of bubbles indicates that the combustion prechamber is leaking compression. This is an expensive issue to fix, and usually the head has to come off to really rectify it. Turn and run.
• On the 300D 2.5 and E300, the electronic diesel system may not be working properly after 15-plus years. Make sure that these accelerate well without excessive noise or surging. EDS issues are not easy to track down, and most mechanics dealt with them by rerouting vacuum lines.
• Look for signs of a vacuum pump replacement. These pumps were notorious for failing, and then causing major timing chain and oil pump damage. They are not expensive, but it is nice if they have been already been replaced.
• On the 300D 2.5, check the timing chain. For unexplained reasons, original chains stretch prematurely. If it has been replaced, make sure it was done correctly.
• These cars do not tolerate veggie oil well. Unlike the old 61x engines, the 60x engines suffer from long-term issues after running on it.

Value Guidelines

 *Add 10-15 percent for Sportline models

• A Condition – Potential class winner at regional concours
• B Condition – Safe and attractive for club events
• C Condition – Complete but requires repair or restoration

An excellent example of the 400E, owned by Albrecht Stachel

Ask an Owner

The 400E is the hidden jewel of the W124 series of cars. It shares with the 500E the modifications that reinforce the body structure, the M119 engine family, suspension and brake upgrades, as well as other details such as a large-capacity alternator (110 amp), larger drive shaft diameter, additional rear cradle links, and so forth. The interior appointments are standard W124 fare, but most of the 400Es sport fancier wood veneer.

Driving the car, it becomes quickly noticeable that the body structure affords a sense of being hewn out of billet. The increased stiffness translates into crisp suspension and handling responses, bolstering confidence, and it is unquestionably a tick up from the standard W124.

The 400E appears to be slotted as the E-Class freeway cruiser, with a very tall 2.24:1 differential ratio. At 60 mph the engine is at loafing at 1,700 rpm in 4th gear. On a recent trip of 2,700 miles my car was able to achieve a high of 29 mpg. In average daily driving on our rural roads, the car tends to get about 25 mpg. The 4.2-liter engine spools out power effortlessly in concert with the 4-speed transmission. The car starts from a stop in first gear, then quickly shifts up through the gears.  As with the 500E, even with heavy braking, the brakes scrub off speed in a dignified manner with no drama.

Interior of the 400E, not much different from the other W124s

The 400E definitely is suitable for all occasions, user-friendly and fuel efficient, especially for a V-8 engined car and nearly as good as the 300D.   It also has some of the better seats in the collection.  I keep thinking, “Wow, this is the all-around best handling car I own.”  I am amazed at the serene nature of how the machine does its job.  In short, it’s a joy to drive.

Compared to newer models, I think the W124 series cars have a Teutonic visual essence lost in the subsequent designs.  Of course, I had to personalize my car, replacing the original wheels with 16-inch W120 wheels, which I think makes the car look tougher, and I like the “sand dollar” appearance of those wheels.  I also substituted Euro lights, because they are more efficient than U.S. spec lights and make the front end look cleaner.

With 99,000 miles on the odometer and routine maintenance, I have not had any problems. The engine computers seem to keep the engine in a constantly perfect state of tune, great! The exhaust is still factory.  I change transmission fluid every 20,000 miles because these 722.35 transmissions seem not as durable as earlier variants. I have bathed the vehicle in paraffin preservation to protect against corrosion.

If you cannot find, or do not trust a 500E, get a 400E for lots less money; but do it before the genre gets recognized by the general market.

 - Albrecht Stachel

1984-1995 W124 Technical Specifications

* Turbodiesel  ** Station Wagon