In order to replace the outdated M123 engine, Mercedes developed the M103 E26 engine in 1985. A 2.6-liter power unit with a cylinder diameter of 82.9 mm was developed based on the M103 E30.
M103 E26, M103 E30, M104 E28, M104 E30, M104 E32, and M256 E30 are members of the R6-family.
The M103 E30’s cylinder head is modified for the E26; the intake and exhaust valves’ diameters are lowered from 43 to 40 mm and 39 to 35 mm, respectively. Mechanical injection is the fuel injection system. A single row chain that is susceptible to tension is used by the timing drive. KE-Jetronic is the fuel supply system.
Specifications
| Production years | 1985-1993 |
| Displacement, cc | 2597 |
| Fuel system | KE-Jetronic |
| Power output, hp | 160 – 165 |
| Torque output, Nm | 220 – 230 |
| Cylinder block | cast iron R6 |
| Block head | aluminum 12v |
| Cylinder bore, mm | 82.9 |
| Piston stroke, mm | 80.2 |
| Compression ratio | 9.2 |
| Features | no |
| Hydraulic lifters | yes |
| Timing drive | chain |
| Phase regulator | no |
| Turbocharging | no |
| Recommended engine oil | 5W-40 |
| Engine oil capacity, liter | 6.0 |
| Fuel type | petrol |
| Euro standards | EURO 0/1 |
| Fuel consumption, L/100 km (for 190 E W201) — city — highway — combined |
12.4 8.2 10.2 |
| Engine lifespan, km | ~450 000 |
Disadvantages of the M103 E26 engine
Lubricant leaks are the most common issue that car owners with such a power unit deal with.
The crankshaft oil seal and the U-shaped gasket are the areas where leaks could occur.
Engine failure brought on by clogged injectors is the second most frequent issue.
The valve stem seals are typically the cause of the oil burner, which disappears when they are changed.
A single-row timing chain may already be stretched after 150,000 kilometers and need to be replaced.