In this article, we find out which diesel engines Mercedes Benz used in the 1980s? Which models produced by Mercedes Benz had diesel engines? Is the 1980s Mercedes diesel reliable? And should you buy it?

Which diesel engines did Mercedes Benz manufacture in the 1980s?

Mercedes Benz is one of the leading manufacturers of automobiles that played a significant role in the development of diesel engines. In the 1980s, Mercedes Benz mainly used the 601, 602  Diesel engines.

The OM601 is an inline 4 cylinder engine with displacement between 2.0-2.4 litres depending on the models it was used. It had a very long production run from 1983-to 2001. Similarly, OM 602 was a higher displacement engine with one extra, used from 1985-to 2002. 

Diesel engines are self-igniting engines, they don’t require additional ignition systems to ignite the fuel mixture in the combustion chamber. The diesel is compressed and as the air gets heated due to compression pressure, the diesel fuel ignites.

OM 601 and OM602 are mostly over-square engines with long strokes and as the compression pressure is very high, the overall weight of the diesel engine is higher compared to petrol engines. The cylinder heads were constructed using aluminium and engine blocks were made up of cast iron.  

There is an engine oil lubricating circuit inside the engine block and cylinder head. The oil pump driven by the crankshaft circulates engine oil inside the oil sump to all the moving parts of the engine. Engine oil reduces friction between the moving parts and prevents premature wear of critical engine components.

The power output of OM 601 and OM602 was from 72 hp- to 127hp, both the engines developed superior torque and they were also used in a few commercial vehicles. 

Which Mercedes Benz models had diesel engines in the 1980s?

The OM 601 was a popular choice for the vans while the OM 602 was used for a few passenger cars. Following are the models with OM601/602 engines.

•  W201 190 2.5 D
• W124 250D
• T1 model (208D, 308D, 408D)
• Mercedes Benz Sprinter 308 D

Mercedes Benz also provided OM601/602 engines to companies like SsangYong, Force motors limited. Force motors even uses the OM602 engine even today in some of the models like Force Traveller and Gurkha.

The engines were available in turbocharged and naturally aspirated forms; in the sprinter models, the OM 602 utilised the direct injector method for fuel injection. Although the most common rail diesel injection method was not widely used in the 1980s, the high-pressure fuel pumps were used with mechanical governors and vacuum-operated stop control systems.

This allowed the engines to have altitude compensation and load sensing automatic idle speed adjustments. The high-pressure fuel pump was also lubricated by engine oil instead of using diesel fuel for lubrication.

Is the 1980s Mercedes diesel engine reliable?

Yes, the Mercedes diesel engine OM601/602  was a very reliable diesel engine. Some of the W124 models even exceeded 1000,000 miles, hence the OM601/602 are one of the most reliable engines produced in the 1980s. 

The camshafts are housed in the cylinder heads and driven by a chain connected to the crankshaft. The same chain drive also drives the inline high-pressure fuel pump, camshafts operate on a hydraulically compensating valve lifted. Therefore, major engine repair tasks like the valve setting are not necessary and the engine can continue to operate without any issues. 

The timing chain drive is also very durable and lubricated in the same engine oil lubricating circuit. No issues like timing chain elongation, engine misfiring were reported by the customers even after covering more than 500,000 miles.

Due to the oil crises in the US, the demand for diesel increased and Mercedes Benz with its leading diesel engines exported many units to the United States of America. Both the Om 601 and Om 602 engines had a Closed deck engine design, 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.

The engine block was strong to withstand extra stress exerted by boost pressure generated in the turbocharged versions. No additional modifications were necessary between naturally aspirated and turbocharged engines.

The glow system consisting of glow plugs and output stage relay was capable of heating the combustion chamber before starting the engine and also continuing the post glowing phase to bring the engine to its operating temperature.

The overall consumption of the glow plugs was only 8- 10 Amps and didn’t cause any malfunctions during the entire service life of the vehicle.

The service scope of OM 601/602 engines only included engine oil and oil filter change. 

If the engine oil and oil filter is not replaced periodically then engine oil loses its lubricating properties and can no longer do an adequate task of lubricating moving parts.

 Engine oil filter is also a very critical component as it filters small metal shavings in engine oil which can scratch and damage bearings inside the crankcase. Small particles if left unfiltered in the engine can block the lubricating path or oil spray nozzles and cause wear to components like the timing chain, valves, connecting rods and cylinder walls.

Should you Buy the 1980s Mercedes Benz Diesel car?

Mercedes Benz cars can easily last more than 10 years provided they are used and maintained properly. Although the electronic systems used in the 1980s diesel cars like W 201 and W124 are very simple, electrical wiring harnesses degrade and they can require repairs or replacements.

The diesel engines don’t have any major issues but the cost of spare parts and Labour in the Mercedes Benz workshops is on the higher side. Any additional jobs or restoration work can easily cost more than thousands of dollars.

Many speciality workshops specialise in the restoration of 1980s Mercedes diesel models by mostly using restored parts or salvaging good parts from the scrapped cars.

These vehicles were mass-produced so there are plenty of used 1980s 250d available, however good example cars are rare. W124 is extremely popular among car enthusiasts due to its looks and driving dynamics.

The suspension systems on the W124 and W201are robust and don’t require a major overhaul. The cost of the spare parts apart from the electronic control units & relays is reasonable.

Other articles about Mercedes Benz you may be interested in

What is the oil type of the 2013 Mercedes Benz E 350?

Does the Mercedes Benz E350 have a remote start function?

What is the horsepower of the Mercedes Benz C43 AMG?

Conclusion

After the huge success of the OM617 engine, Mercedes Benz needed updated engines to comply with emissions rules. The small displacement and turbocharged OM 601/602 diesel engines produced more than 100 hp and kept the emissions within the limit. These engines also laid the foundations for the development of the Mercedes Benz Bluetec diesel engines that were used in all different classes in the 2000s. 

FAQs: which diesel antigens did Mercedes Benz manufacture in the 1980s?

Is old Mercedes diesel reliable?

Yes, Old Mercedes diesel engines are reliable. There were no reliability issues even after completing 100,000 km. They used hydraulic tappets and overhead camshafts so common jobs like valve adjustment were no longer required.

What Mercedes models have a diesel engine?

Mercedes Benz gives a diesel engine option in every class currently on sale today. The diesel engine is also a popular choice as the cost of petrol is very high in some international markets.

What year Mercedes diesel engine is the best?

The OM617 diesel engine made in the 1970s is considered the best Mercedes Benz diesel engine. The latest diesel engines OM654 and OM656 are also very advanced and runs cleaner than some petrol engines.