For enthusiasts of classic Mercedes-Benz vehicles, the 1987 300D often sparks lively debate. While opinions may vary, many agree that this model represents a sweet spot in Mercedes diesel engineering. Stepping beyond the older W123 series with their less powerful OM617 engines, the 1987 300D (W124 chassis, OM603 engine) ushered in a new era of “modern” Mercedes diesels, boasting enhanced power, improved handling, and greater fuel efficiency. Its design language was so influential that it was widely emulated, and even today, the W124’s styling retains a fresh and contemporary appeal. Owners frequently report fuel economy figures of around 25 MPG in city driving and upwards of 30 MPG on the highway, although individual results may vary.
Mercedes-Benz first introduced the W124 chassis with gasoline engines in Germany in 1985, bringing them to the United States in 1986. The year 1987 marked a significant milestone with the introduction of the OM603 diesel engine. This engine featured an alloy cylinder head, a departure from the iron heads of previous models. While the alloy head offered performance benefits, it was known to be more susceptible to cracking if the engine overheated. Mercedes-Benz addressed this concern by implementing improvements to both the cylinder head and head gasket in later iterations, enhancing their robustness. However, vigilance regarding the coolant temperature gauge remains prudent. It’s advisable to avoid pushing the engine if the temperature begins to exceed approximately 110 degrees Celsius.
Early versions of the OM603 cylinder head are identifiable by a part number containing “14.” Subsequent revisions featured “17,” “20,” and finally “22.” While a “14” head shouldn’t necessarily be a deal-breaker, when possible, opting for a later version is preferable. The presence of an earlier head type can be leveraged as a point of negotiation during purchase. It’s worth noting that many owners, including those with the #14 head, have experienced no issues, particularly when the cooling system is well-maintained and operating temperatures are closely monitored.
The reason behind Mercedes-Benz discontinuing the OM603 engine after the 1987 model year remains somewhat unclear. Speculation points to potential cylinder head issues or increasingly stringent emissions regulations. Around 1990, Mercedes introduced a 5-cylinder turbodiesel variant, the OM602. The final W124 models, produced in 1995, featured the OM606 6-cylinder naturally aspirated engine. As the W124 series evolved, it incorporated more and more electronic systems. Consequently, the earlier models, like the 1987 300D, are generally considered simpler and potentially easier to maintain for those who prefer a more hands-on approach to vehicle care.
Prospective buyers of a 1987 Mercedes Benz 300d should be aware of several potential areas that, while easily overlooked, can lead to costly repairs. These include cylinder head cracks or blown head gaskets, suspension system issues (which can be challenging to detect during a cursory inspection), climate control malfunctions (often deceptively presented as simply needing a recharge), and sunroof problems (the W124 introduced Mercedes-Benz’s first slide/tilt sunroof, which had some initial design shortcomings). Addressing these issues can each potentially incur expenses reaching thousands of dollars. Cruise control failure is another relatively common problem, though typically less expensive to rectify, with rebuilt control units available for around $300.
Conversely, numerous aspects of the 1987 300D are within the scope of DIY maintenance and repair. Owners can save significantly on labor costs and parts by sourcing components from reputable suppliers and tackling tasks such as suspension work and climate control maintenance themselves. While sunroof repairs might be more complex and best left to professionals, many routine maintenance procedures are accessible to the home mechanic. These include oil changes, fuel and air filter replacements, glow plug replacement, light bulb changes, and basic wiring repairs.
The increasing prevalence of W124 gasoline models (300E) in junkyards is advantageous for 1987 Mercedes Benz 300D owners. Given that the body and interior components are largely shared, a wealth of affordable body panels, interior trim, and miscellaneous parts are readily available.
The W124 chassis platform marked a significant advancement in terms of passenger comfort and convenience features compared to its predecessors. However, this also translates to a greater number of systems that may require maintenance over time. The 1987 300D is equipped with features such as ABS anti-lock brakes, a driver-side airbag, power-adjustable seats with driver’s seat memory, and retractable rear headrests, all of which were relatively advanced for their time.
The decision of whether to embrace or avoid a classic vehicle like the 1987 Mercedes Benz 300D often hinges on an individual’s aptitude and inclination towards vehicle maintenance and repair. For those who rely on professional mechanics and pay retail prices for parts, the adage that there’s no such thing as a “cheap” Mercedes-Benz certainly rings true. However, by acquiring DIY skills, owners can potentially reduce maintenance costs by half or more.
The 1987 300D features the robust 722.4 4-speed mechanical automatic transmission, initially introduced in the later W123 models. This transmission is known for its reliability and longevity, often exceeding 200,000 miles. While overhauling this transmission is comparable in cost to most other automatic transmissions, it’s generally not a DIY undertaking for most owners.
Extensive information regarding the 1987 Mercedes Benz 300D and W124 chassis is readily available through online forums and owner communities. Prior to purchasing a 1987 300D, it is strongly recommended to have it thoroughly inspected by a qualified professional Mercedes-Benz mechanic. Investing in a pre-purchase inspection can potentially save thousands of dollars in unforeseen repairs down the line – a lesson learned by many experienced owners.
