When I first laid eyes on the 1999 Mercedes Sl500 at my Uncle Dave’s workshop in New Hampshire, I was immediately captivated. Despite needing some attention, its beauty was undeniable, sparking a thought: if I were to buy a car, why not choose one that truly appealed to me? This SL500, just a year older than myself and with 121,000 miles on the odometer, felt like a worthwhile venture. My mindset was simple and perhaps a little naive: any issues that arose could be tackled head-on.
Having saved diligently, I purchased the car and began the long drive back to Virginia. A stop in Massachusetts to visit my Aunt Karen and Uncle Erik marked the beginning of my Mercedes ownership experience in a rather dramatic fashion. The hydraulic system for the convertible top’s locking mechanism decided to express its displeasure by leaking fluid. Fortunately, some paper towels and quick thinking prevented any damage to the interior. Little did I know, this was just the first in a series of adventures with my newly acquired SL500.
Shortly after leaving Massachusetts, the engine started misfiring. Being unfamiliar with such issues, I pressed on. The SL500, equipped with 16 spark plugs for its eight cylinders, managed to run reasonably well even with a faulty plug, as each cylinder would still fire. Upon arriving home, curiosity led me to inspect under the hood, eager to understand what was happening within the engine bay of my 1999 Mercedes SL500.
I sold the car but I miss it. I learned a lot of skills and a lot about cars. I went into this knowing nothing to now knowing most of what you could know.
Seeking professional advice, I took the car to a local repair shop to diagnose the check engine light. This experience quickly highlighted a crucial lesson: shops accustomed to modern vehicles may not possess the specialized knowledge required for older, particularly European, luxury cars like the SL500. The technicians, while competent with newer models, lacked the specific training for my car. Faced with this realization and the anticipated costs, I opted to bring the car home and embark on a journey of self-education and DIY repair.
Suspecting the issue to be either coil packs or spark plugs, I began a process of elimination. By systematically swapping coil packs and using AutoZone to read the fault codes after each adjustment, I gradually narrowed down the problem. This iterative process of testing, resetting codes, and retesting eventually revealed two spark plugs that were not firing correctly. Replacing all the spark plugs seemed to resolve the misfire, and the car ran smoothly for a while.
My ownership of the 1999 Mercedes SL500 was a continuous learning curve. Replacing the fuel injectors, for instance, turned into an unexpected ordeal. Initially, I attempted to just replace the O-rings, but achieving a proper seal proved incredibly challenging. Ultimately, the solution was to invest in new injectors complete with pre-installed O-rings. This task, like many others, was a first for me. During reassembly, minor components like bolts would sometimes break, adding to the complexity. One particularly frustrating incident involved having to drill out a broken screw – a less than ideal situation.
The convertible top hydraulics presented another significant challenge. To save money, I attempted to rebuild the hydraulic cylinders myself. While this initially worked, it proved to be a temporary fix. The small seals, which I couldn’t install with the precision of a machine, eventually failed under the system’s high pressure. Hoping for the best, I began using the convertible top, but the inevitable happened – a line popped, and hydraulic fluid sprayed once more. In the end, opting for remanufactured pistons was the only lasting solution.
One advantage of purchasing this particular 1999 Mercedes SL500 was that it came with a hardtop. This became invaluable when the soft top deteriorated beyond repair. Daily driving took its toll, and the soft top went from pristine to riddled with holes within a few months. Whenever the weather was favorable, I would remove the hardtop and store it in my parents’ garage, enjoying the open-air driving experience while possible.
Brake maintenance, both front and rear, was another essential task. Upgrading the rotors turned into a major headache due to a seized caliper pin. Despite considerable force with a hammer, it wouldn’t budge. In desperation, I took the components to a local Mercedes-Benz dealership. The service representative seemed rather taken aback when I presented just the car parts, a stark contrast to the usual clientele dropping off entire vehicles for service and collecting loaner cars. Nevertheless, I did rely on the dealership’s diagnostic expertise on a few occasions for more complex issues. While I was prepared to undertake the repairs myself, accurate diagnosis was sometimes beyond my capabilities at that stage.
An intake manifold air leak was another substantial repair. Replacing the manifold was a complex undertaking, requiring the removal of coil packs, spark plugs, and numerous vacuum lines, all of which needed to be correctly reconnected. The reassembly process was daunting, particularly remembering the precise locations for all the components. However, to my astonishment, upon turning the key after completing the job, the engine roared to life. The subsequent test drive was nerve-wracking, expecting something to go wrong with such a complex repair done for the first time. Yet, it worked flawlessly.
Even routine maintenance tasks could present unexpected moments. When replacing the fuel filter, I neglected to depressurize the fuel system, resulting in a face full of gasoline – a memorable, if unpleasant, learning experience.
Reflecting on my time with the 1999 Mercedes SL500, I would hesitate to recommend a project car, especially a complex Mercedes-Benz, as a first vehicle. The intricate computer systems alone add layers of complexity. There were periods when I felt I was perpetually working on the car, barely keeping pace with repairs and the associated costs. This financial aspect was a primary motivator for tackling the repairs myself; professional labor costs would have been prohibitive.
Despite the challenges, selling the car was bittersweet. I genuinely miss it. The 1999 Mercedes SL500 was an extraordinary teacher, imparting invaluable skills and a deep understanding of automotive mechanics. My initial automotive ignorance transformed into a comprehensive knowledge base, particularly about the SL and cars in general. This journey has ignited a passion for car repair and maintenance, and I am already contemplating my next automotive project. Perhaps an old Triumph, although my height might be an issue. Alternatively, a 5-speed 1992 Mercedes 300SL, ideally in blue, would be a dream.
