There are premium cars on the secondary market at very tempting prices. Despite many cheap but reliable used Mercedes-Benz, Audi, and BMW cars, potential buyers approach the purchase with due attention. Even very technologically advanced Germans sometimes end up with disastrous models and modifications that often break down seriously, and their repair can cost the owner half the cost of the car. In this article, used car experts from the Indianapolis auto dealer Indy Auto Man reveal those Mercedes, BMW, and Audi models that, with a high degree of probability, have several manufacturing defects.
Mercedes cars to avoid
Mercedes-Benz ML W164 is a very nice crossover, produced from 2005 to 2011. Despite the beautiful appearance, pleasant interior, and good driving performance, the car has some problems. In addition to the three-liter diesel engine, the most common is the gasoline M272 – V6, with a volume of 3.5 liters and a power of 272 horsepower. This motor has a small clearance of the cylinder-piston group. Due to environmental requirements, it has a very high thermostat response temperature, causing the engine to operate at extremely high degrees. The slightest contamination of radiators leads to overheating, especially in a big city like Indianapolis, where the car is often in traffic jams. If radiators are not washed regularly, even a slight increase in temperature will lead to scoring on the cylinder walls.
Several cars, including crossover GLK, C, E, S, CLS class, and others have the same engine. If purchasing a Mercedes with this engine, an endoscopy should be a mandatory addition to the standard check. However, experts do not recommend buying a car with this unit, especially after many years of use.
A Mercedes-Benz with four-cylinder M271 1.8-liter engines also deserves additional attention – the most common modification has a power of 184 horsepower. This engine is installed on the C and E classes. These cars still have a current appearance and are attractive at an affordable price, combined with a beautiful design.
The main problem with the engine of these vehicles is the gas distribution mechanism. A thin chain disables the camshaft stars; they are also phase regulators in this engine. It is easy to check their condition before purchasing only by unscrewing the valve cover.
Audi models with problematic engines
A3, A4, A5, TT models, on which TFSI EA 888 GEN 2 motors were installed (1.8 CDA, 2.0 CONC), as well as A1, A3, A4 with EA111 engines (1.2 CBZA, CBZC, CAXA, 1.4 BLG, BMI, BWK, and others) – all these engines have problematic turbocharging. The most frequently broken engines are the 1.4 170 hp. They have both a compressor and a turbine. In harsh Indiana conditions, partitions often crack, and pistons melt. These cars also require a lot of fuel.
In models before 2013, oil scraper rings were very thin. Since 2012, these rings began to be made a couple of times thicker, and the problem has practically gone away. Also, the above engines are equipped with a direct injection system. Due to wear of the fuel pump rod, gasoline gets into the oil, the phase regulator mechanisms and crankshaft liners fail, and the camshafts lift.
Unreliable BMW models
550i, 650i, 750i, X5 50i, X6, and 50i models – all cars with N63B44 engines (4.4 V8 405 hp) look brutal and have a powerful but painful heart. It is indeed very fast but extremely unreliable. This engine has two turbines hidden inside the piston block. There is a huge temperature between them, and one of its main problems is cooling the cylinder block.
Experts do not recommend buying these cars, even in good condition. The problems listed above can arise, resulting in expensive and, most likely, time-consuming repairs.
