Mercedes M103 3.0L Engine Specs, Problems, Reliability. Mercedes began produced of the M103 3.0-liter inline six-cylinder engine in 1985. It was developed for replacing the out-of-date M110 engine. The M103 engine has actually unified style with 4-cylinder M102 series. The M103 series likewise consists of the 2.6-liter variation (the M103 E26 ).
The engine has the light-weight cast iron cylinder block, aluminum cylinder head with two valves per cylinder, a single overhead camshaft, and hydraulic lifters/tappets. There is SOHC setup of the valvetrain for reduction of the engine weight and production cost. Valves are the same as 2.0-liter M102 (consumption valve diameter – 43 mm; exhaust valve diameter – 39 mm).
The engine has a mechanical fuel injection, which is very challenging to change and repair (KE-Jetronic). There is a single-strand timing chain. The M103 was wholly removed from the production in 1993 and replaced by the M104 series 3.0 l engine.
M103 E30 3.0 l Engine Problems and Reliability
1. Unstable engine speed. Bad injector nozzles cause this extremely frequently and the common concern.
2. Oil leaks. Oil likes to leakage from crankshaft oil seals and the U-shaped front cover gasket. Valve stem seals are not extremely great and can be the reason for high oil usage.
Mercedes M103 3.0L Engine Specs
|Manufacturer||Stuttgart-Bad Cannstatt Plant|
|Cylinder block material||Cast iron|
|Cylinder head material||Aluminum|
|Fuel system||Fuel Injection|
|Number of cylinders||6|
|Valves per cylinder||2|
|Type of internal combustion engine||Four-stroke, naturally aspirated|
|Compression Ratio||9.2 (10)|
|Torque, lb ft||188-192/4400-4500|
|Engine oil weight||0W-30, 0W-40, 5W-30, 5W-40, 5W-50, 10W-40, 10W-50, 15W-40, 15W-50|
|Engine oil capacity, liter||6.5|
|Oil change interval, mile||6,000|
|Applications||Mercedes-Benz 300 E W124 (M103.980), Mercedes-Benz 300 SE W126 (M103.981), Mercedes-Benz 300 SL R107 (M103.982), Mercedes-Benz 300 SL R129 (M103.984)|