1968-1976 W115 Sedans
Practical and Reliable, Gasoline or Diesel
A buyers guide to 1968-1976 220s, 230s, 240s, and 300s
 
Article by Pierre Hedary
Photography by Stewart Carter

Both practical family heads and economical taxi drivers instantly wanted the “New Generation” W115-chassis Mercedes-Benz  when it was introduced in late 1967 for model year 1968. 

Initially marketed as 200s and 220s, the cars were equipped with 2-liter engines in Europe, and 2.2-liter engines in Europe and the U.S. in both gasoline and diesel variations.

They were produced with several engine upgrades through 1976, including  three 4-cylinder gasoline engines, and a 4-cylinder and a 5-cylinder diesel engine. These sturdy workhorses were noted for their excellent value, and many are still in use today.

Though not as glamorous as the roadsters and luxury sedans, they continue to be a sensible alternative for the individual who actually wants to drive and use his or her “classic” Mercedes-Benz.

Background

When introduced, the cars featured the all-new M115 gasoline engines of 2.0 and 2.2 liters, and the new OM615.91 diesel engines of the same capacities. The 2-liter engines were reserved for the European markets, particularly for areas where engines over 2 liters were taxed. The U.S. market received only the 2.2-liter engines. The gasoline engines produced 105 brake horsepower (DIN), though the 2.2-liter diesel engines produced 57 horsepower.

Despite their low power, especially in the diesels, these cars can run with traffic in areas that are not horribly congested. While performance is leisurely, it is still realistic, as the cars can cruise at 75 mph with some room left for higher speeds. Relatively good fuel economy, especially in the diesels, and their 4-wheel disc brakes, independent suspension, and good air conditioning makes these solid cars good daily drivers.

Standard equipment included 4-wheel disc brakes, viscous-clutch cooling fan, 4-speed manual transmission, independent suspension on all four wheels, fuel injection (the only way to have a diesel anyway), and vinyl seats.

Options included air conditioning, short-wave radio adapter, power or manual sliding roof, power windows,  Becker Europa radio or Grand Prix radio, power steering, 4-speed automatic gearbox with floor or column gear selector, arm rest, rear radio speaker, fog lights, outside right-hand mirror, oil cooler, power antenna, head rests, seat belts (often installed after assembly by American Safety or Kangol), trailer hitch, and self-leveling rear suspension (Europe). In Europe, they also could be ordered in wagon body style or long-wheelbase bodies.

These cars instantly became the bread and butter of the Mercedes-Benz range, with taxi drivers lining up to purchase them and families ordering them as early as possible. These cars replaced the W110 Fintail cars, and with the new, quiet, and flexible 615 motor, the idea of owning a diesel became more appealing.

The 220 and 220D were improved through the years, with updates to the a/c controls, and better, more user-friendly speedometers, light switches, head rests, seat belts, gear-shift levers, and so forth, in 1970. In 1973, the type of vinyl used on the seats and the steering wheel was replaced with safer though less lovely material. Also, from 1973, central locking could be supplied.

In response to the gas crisis, a new version of the 4-cylinder gasoline engine, with different bore and stroke, measuring 2.3 liters, was introduced in late 1973 as the 230, followed in 1974 by a 2.4 liter five-cylinder diesel with improved fuel efficiency and performance.

From model year 1974 (September 1973), bigger bumpers and new engines were the feature for our market. The new 240D used the OM616.916 engine, with a manual gearbox standard. Radio, headrests, seat belts, oil cooler, and power steering were all standard on U.S. cars.

The 300D was introduced in September 1974 and became available in 1975. It used the 617.910 5-cylinder engine. Automatic gearbox, central locking system, air conditioning, power steering, deluxe radio with four speakers, and fog lights were standard on these lovely cars. They and the 240Ds could be had with a cruise-control system for 1975-1976. Production of the W115s ended in August 1976.

Reasons to buy a W115
 

• Good fuel economy and reliability.
• Wonderful handling, steering, and brakes. All models had 4-wheel disc brakes and newly-designed independent suspension.
• Stylish design in a stolid sort of way, with spacious interiors, a high greenhouse with good visibility, comfortable seats, and excellent crumple-zone crash protection.
• Early cars had a very pure look. Later cars are not as handsome but are even safer in an accident.
• Inexpensive examples are easy to find and major parts are relatively available at reasonable prices.

Reasons not to buy a W115
 

• Rust will have to be addressed, and structural rust can be terminal.
• All have needs, including oil leaks or other maintenance problems.
• Engine, transmission, and suspension rebuilds are pricey.
• Many examples have spotty previous maintenance and worn interiors.
• Acceleration is glacial but highway cruising speeds are adequate.
• The diesel engines smoke – it’s a fact of life, but some smoke less than others.
• Later M-B diesels have many of the attributes of these cars, so the only reason to buy one is because of the way it looks and rides.

Checkpoints
 

• W115 cars like to rust. Rust in the fenders, floor, and trunk is easy to deal with, but rust in the front firewall, around the back window or sunroof, in the structural areas, and in the rear wheel wells is a good reason to look for another example.
• Suspension wear in the front subframe mounts is common.
• Heavy oil consumption indicates a worn engine. It can still be reliable but will require adding oil with every tank of gas.
• Make sure small trim parts and interior items are present and not broken. These parts are quickly becoming either expensive or unavailable.
• Rubber seals are often dried up and can cost up to $1,500 to renew entirely if one uses OEM rubber and has a competent shop do the work.
• Interiors and carpets were not as durable after 1973. Cracked dashboards are a problem, as are headliners, which peel back around the rear window.
• The cars have always been inexpensive, so commensurate shortcut repairs are often seen.
• Heater fans and a/c fans are hard to fix and time-consuming to replace.
• Five-digit odometers mean that true miles will be a secret, unless the owners have kept careful records.
• While these cars are not oil leakers by nature, expect to have to fix a few on your W115.

Nitty-Gritty – Diesel Cars
 

• These are exceptionally reliable cars. Even abused, high-mileage cars seem to keep running. Cars with more than 300,000 miles are not unusual. Even cars that have had horrible maintenance over the years can be revived into good runners. The only thing that really seems to destroy the engines is running them with insufficient oil.
• The engines and drivetrains are easy to maintain. When one understands how to adjust valves, change oil, clean the oil-bath air filter, and perform basic transmission services, these are easy cars for the do-it-yourselfer to maintain. Fuel economy is good, even by today’s standards.
• Worn engines will virtually drink oil. While they will still be reliable, they will continually need oil added. On a 220D, a quart every 350 miles at higher speeds is not uncommon. Anything over a quart every 650 miles is fine on a 240D or 300D.
• These cars drive and handle very well. The sturdy suspensions, 4-wheel disc brakes, separate front and rear subframes, and solid bodies are good in many weather conditions, and the air conditioner actually works if charged properly. With proper soundproofing, new motor mounts, and reconditioned injectors, the diesel engines are relatively quiet.

Nitty-Gritty –  Gasoline Cars

• All 230 and 250 variants up to 1972 used the Zenith 35/40 INAT carbs. The twin-carb setup on these inline-six engines tends to develop problems with age. Exhaust manifold heat can warp the carb castings, causing them to leak gas. Setting up the Zeniths is a little difficult but can be done with a lot of patience. The W108, 109, 111, and 113 service manual outlines the procedure quite well, as the W108 280S and 250S used the same carbs. Poorly adjusted Zeniths will be thirsty but not unreliable. Correctly adjusted ones are quite nice and smooth.
• All 230 and 250 models had valve problems. Original models didn’t have the badly needed rotating caps, leading to some cars needing a complete valve job at 50,000-75,000 miles. The  rotating caps are positioned at the base of the valve spring. Beware of low-mileage examples of 230s and 250s.
• All 6-cylinder models had head gaskets that do not fare well after an overheat. The oil should be checked for coolant, and the coolant for oil.
• All 6-cylinder models do not seem to do well in hot, dry climates. They will overheat at high speeds or in traffic if the engine block and radiator are not perfectly clean.
• 4-cylinder gas models with the Stromberg 175 series carb and lots of emissions equipment tend to need extra attention when they get older. Carb dampers should be filled with transmission fluid, not engine oil.
• 280 sedans have camshaft wear issues that can only be solved with an updated cam box and cams from Daimler. The cam wear should be checked before purchase.
• All of these cars, gas and diesel, had to have valve adjustments regularly. Diesels were set at 15k and gas models at 10k.
• As a rule, manual and automatic gearboxes were similar in gasoline and diesel engines, and they were all very tough.

Buying Tips
 

• Aside from repair of obvious mechanical issues, be prepared to live with the car you buy. Market values leave no room for a repaint or extensive interior repair.
• Unless the car is very nice, or you have a lot of time on your hands, try to avoid 1975 and 1976 gasoline cars because of the emissions equipment mandated in these years.
• Interiors from June 1972 to 1976 were not nearly as durable as on 1968 to early 1972 cars.
• Floor-pan rust is common on these cars, but pans are easy to replace and are readily available from Mercedes-Benz or K&K Manufacturing.
• On 4-cylinder diesels only, the injection pump diaphragm should be assessed. This can be done by decelerating from a high speed, while watching for white smoke and a rough idle when the car comes to rest.
• Watch out for front-suspension wear on 5-cylinder and 6-cylinder models especially.
• On nearly all of these cars, body gaskets and rubber will need to be renewed. The rear-window gasket is no longer available from Mercedes-Benz, but the Febi company makes a good replacement.
• Diesel models will always be easier to service and repair, but watch out for cars that have been driven for years at a time without any service at all. On diesels, even irregular service won’t ruin a car, but oil consumption, engine temperatures, and fuel economy can be used as a meter of engine health.
• Power-window regulators are now hard to find new, but Carquest Auto Parts can order OEM regulators from Brose in Germany.
• Replacement dashboard and other interior trim parts are virtually unobtainable, so you will probably have to live with a few interior flaws.
• Mercedes-Benz still sells parts to repair the seats, but they are pricey. However, the refurbishment is worth it.

Real World Example
 
Our real-world example of the W115 belongs to Stewart Carter , 17, an MBCA member in Jacksonville, Florida.

He writes: “I purchased this stunning 1976 W115 300D, in English Red (DB504) with Bamboo (167) MB-Tex interior, two years ago from a family in Live Oak, Florida, as my first car. The family bought the car from its original owners in the late 1980s when they were living in California. They moved to Live Oak, Florida, in the mid 1990s and had their 1976 300D transported from California to Florida. 

“When the car arrived in Florida it was placed in a barn and driven very rarely. Because this car is an original California car there is virtually no rust on the body. When I purchased the car I immediately replaced all worn parts in the front suspension and in the braking system on which lack of use had taken its toll. This W115-D has many new parts and has proven its reliability; within my two years of ownership I have driven close to 25,000 miles. Many of those miles were acquired by attending a few MBCA club meetings in the state of Florida. You cannot beat the outstanding durability, comfort, and reliability of the Mercedes-Benz W115 chassis.”

“I bought the car for a price consistent with its good cosmetic and average mechanical condition, and think it’s current value is close to the high end of typical market values.”
 

Value Estimates

All models span the same value spectrum, but there are differences between gasoline and diesel values.

Low value is a safe driver but with visible flaws.
Medium value is a car that is well-maintained or partially restored and could be in a local car show.
High value is a car that is in top concours condition – as nice as a new car straight from the factory.

Technical Specifications