Are the Mercedes Benz cars reliable?

In this article, we will find out if Mercedes Benz cars are reliable and answer the questions: what are the materials and special features that make a Mercedes so reliable? how long can a Mercedes last? What are open deck and closed deck designs in Mercedes Benz engines?

Are the Mercedes Benz cars reliable?

Yes, Mercedes Benz cars are reliable due to the following reasons:

  • Durable exterior paint
  • Genuine spare parts
  • Extended warranty programs

Durable Exterior paint

The exterior paint used on the Mercedes Benz is sprayed in multiple layers. It has a protective clear coat that prevents scratches and corrosion of the body. Genuine Mercedes Benz polish and body shampoos are used for cleaning the car after performing periodic maintenance at dealerships.

Genuine spare parts

Genuine parts and accessories offer individual parts warranty of up to 2 years. However, if any part is already replaced under standard or parts warranty, replacing the same part will cost money and the warranty cannot be claimed again. Extended warranties can be bought under the advanced assurance programs. 

Extended warranty programs

The advanced assurance program can cover the vehicle under an extended warranty after the standard warranty of 3 years is over. You can choose to extend the warranty for the fourth or up to the sixth year. The extended warranty can be purchased anytime in the first three years of owning the vehicle and it can be transferred to the new owner if the vehicle is sold.  

A recent study conducted by a UK-based insurance company found that out of the top three German car manufacturers Mercedes, BMW and Audi. Mercedes has the most reliable models and fewer major issues, Audi is the least reliable and BMW is in the middle.

How long can a Mercedes Last?

Records indicate that a Mercedes E class covered more than one million kilometres. It was maintained and used properly by its owner. Mercedes Benz cars can easily last for more than 10 years before any major restoration work is required. 

An extended warranty program and a large dealership network mean maintaining and owning a Mercedes is a pleasurable experience. Mercedes Benz engines have the great built quality and they are used in passenger cars, commercial vehicles and even in boats and aircraft. The three-pointed star in a Mercedes Benz logo indicates total dominance over land, sea and air.

What are the Mercedes Benz engines made of?

Engine block or commonly known as crankcase is the foundation of any engine. Petrol engine blocks are made up of aluminium alloy while diesel engine blocks are made up of cast iron. 

The reason for the change in materials for diesel and petrol engines is because diesel engines are self-igniting, the compression pressure in diesel engines is up to 30 bars. Hence, the material of the engine block must be strong enough to sustain high combustion pressure. 

Cylinder heads for both petrol and diesel engines are constructed using a special alloy of aluminium metal. The cylinder head houses intake and exhaust valves, rocker arms with rollers and hydraulic lifting elements. Camshafts are partially mounted in the cylinder head and cylinder head cover. Therefore the cylinder head cover cannot be replaced separately. The cylinder head must also be replaced together with the cylinder head cover.

Mercedes Benz uses NANOSLIDE coating on the cylinder walls. This is an extremely thin coating applied to the inner surface of the cylinder to reduce friction between the piston. Twin-wire arc spraying (TWAS) is used to spray an extremely thin coat of iron-carbon alloy on the cylinder walls.  The friction between the piston and piston rings is reduced by almost 50 per cent.

What are open deck and closed deck designs in Mercedes Benz engines?

Closed deck engines are more commonly used in Mercedes Benz diesel engines. This type of construction provides more support to the cylinder walls and water jackets can be designed around the cylinder sleeve for better cooling. The use of closed deck design along with cast iron metal makes up for heavy engines.

Open deck design is more commonly used in Mercedes Benz petrol engines. The compression of a petrol engine is between 11 to 16 bars which is very less compared to a diesel engine. This constitutes less combustion pressure and aluminium alloy can be used for the construction of crankcase.

Special features are found in Mercedes Benz to increase reliability.

  • Warm-up phase

When the engine is started for the first time, engine oil and coolant temperature are low. The engine is designed to operate at a specific operating temperature and must also reach this operating temperature quickly regardless of the outside temperature. Hence, in the warm-up phase, the engine idles at slightly higher RPMs for a few minutes after starting the engine. This also ensures the engine oil is circulated to the entire engine.

  • Radiator shutters

Aerodynamic flaps are not only present on the outside of the vehicle but also inside the vehicle. Flaps cover the surface of the radiator and are operated by a vacuum actuator. 

By closing the flaps air does not flow over the surface of the radiator and coolant can heat up faster which is then pumped back into the engine and the operating temperature is reached more quickly.

  • Multi-Spark ignition system. 

This is only used in petrol engines. Spark plugs generate an ignition voltage of 15000 to 45000 volts in a Mercedes Benz petrol engine. Multi spark mode is active during the warm-up phase and instead of discharging the ignition coil completely, it is changed again in small intervals. This results in multiple sparks which increase the combustion temperature and the engine can reach the operating temperature more quickly.

Common practices increasing the Reliability of Mercedes Benz cars

  • After starting the engine, wait for a few seconds so the warm-up phase can finish. This also makes sure the engine oil is circulated entirely in the engine.
  • Never operate the engine in full loads for an extended duration, keep the RPMs fluctuating. Operating an engine at constant or high rpm puts unnecessary strain on the engine components.
  • Visually inspect the engine compartment for visible oil or coolant leaks. If the oil or coolant level is low then the engine can be damaged due to overheating.
  • Consult the workshop if an EOBD malfunction or abnormal noise is coming from the engine while driving.
  • Follow the service schedule and replace parts like air filters, fuel filters etc so the engine can continue to function properly.

Other articles about Mercedes Benz you may be interested in

Which are the reliable Mercedes Benz models in the 90s?

Is the Mercedes E320 a good car?

What are the most reliable SUVs produced by Mercedes Benz?


Great built quality and larger after-service network mean Mercedes can last longer and if any unexpected repairs occur, they can be fixed easily. Years of research and rigorous tests are carried out before launching a Mercedes Benz car. Hence, Mercedes Benz is the most reliable German car manufacturer.

What was missing from this post which could have made it better?

Leave a Comment