Mercedes-Benz diesels are some of the best vehicles ever built and hold the Guinness World Record for longevity. With basic maintenance-regular oil changes, valve adjustments every two years, and so on-you can expect your engine to last 500,000 miles. The entire vehicle is built incredibly well, and now that they're old enough to be considered classics, there are some common issues you may notice.
Greek taxi driver Gregorios...
Greek taxi driver Gregorios Sachinidis holds the Guinness World Record for the highest mileage in a car. His 240D has more than 2,858,307 miles on the odometer. You can expect about 500,000 out of a Mercedes-Benz diesel engine if you take care of it.
1. Engine: Although they're often gutless and smoky, more often than not, they're easy to bring back to life. Smoke on initial startup is normal, and new Bosch glowplugs will help-as well as an oil stabilizer, like Lucas. If it's a turbo, at least 90 percent of them can regain power and performance by a simple adjustment of the ALDA valve, which increases fueling when turbo boost is present. Some smoke on acceleration is normal, and adjusting the ALDA valve can also help this. If you have smoke at a steady cruising speed, it's a sign of excessive engine wear, and thicker motor oil is the easiest way to buy more time. A long freeway drive is the quickest way to smooth out a neglected engine.
2. Transmission: If you have an automatic transmission, it can be expected to last between 175,000-200,000 miles. Although these transmissions are solid, they're quirky and often have issues that feel more serious than they actually are. Hard shifts are common and can usually be adjusted out. Revving between shifts is also adjustable, but it's often a sign that the transmission is on its last legs. Low power is often a transmission issue. They start off in Second gear, and if the transmission doesn't kick down to First when needed, it will result in very sluggish acceleration. Driving in "S" around town will change your shift points, resulting in more responsive acceleration.
3. Power windows: These are a very common problem as the cars age. Most often, the switch itself has corrosion in it and can be cleaned or replaced. People use the switch panel as a drink holder, and there is almost always crud and dirt in the switch contacts. Although Mercedes charges up to $100 for replacement switches, try a wrecking yard or eBay for a better deal.
4. Leaks: These cars mark their territory; that's all there is to it. Fix a drip and another will follow shortly. If you're frequently topping off your oil, you have a problem that needs fixing, otherwise, get used to it. If fuel is leaking on or around injectors, your return lines need to be replaced. Simply pull them off and push on new ones. Don't skimp; use Mercedes-Benz rubber return lines from Germany.
5. Maintenance: These cars are cheap and easy to maintain because they lack the following: carburetors, spark plugs, wires, distributor caps, rotors, and so on. Just make sure to change your motor oil and filter often-and never run out of oil or coolant. The most common causes of engine failure are running out of motor oil and overheating. Use good Bosch glowplugs, Delo 15W-40 oil with Lucas stabilizer (if needed), and adjust your valves every two years. Your Mercedes will start and run like a dream.