Produced between 1983 and 1991, the 2.4-liter BMW M21 or M21D24 diesel engine was fitted to the company’s well-known models, the 3-Series in the rear of the E30 and the 5-Series in the rear of the E28 and E34. Both an atmospheric and a turbocharged version of this unit were available.
The engine was installed on:
- BMW 3-Series E30 in 1985 – 1991;
- BMW 5-Series E28 in 1983 – 1987; 5-Series E34 in 1988 – 1991;
- Lincoln Continental Mark VII in 1984 – 1985.
Specifications
| Production years | 1983-1991 |
| Displacement, cc | 2443 |
| Fuel system | vortex chamber |
| Power output, hp | 86 (M21D24 or M21D24S) 115 (M21D24 Turbo or M21D24T) |
| Torque output, Nm | 152 (M21D24S) 210 – 220 (M21D24T) |
| Cylinder block | cast iron R6 |
| Block head | aluminum 12v |
| Cylinder bore, mm | 80 |
| Piston stroke, mm | 81 |
| Compression ratio | 22.0 |
| Features | no |
| Hydraulic lifters | no |
| Timing drive | belt |
| Phase regulator | no |
| Turbocharging | no (M21D24S) Garrett T3 (M21D24T) |
| Recommended engine oil | 5W-40 |
| Engine oil capacity, liter | 5.5 (M21D24S) 5.75 (M21D24T) |
| Fuel type | diesel |
| Euro standards | EURO 0 |
| Fuel consumption, L/100 km (for BMW 524td 1986) — city — highway — combined |
9.5 5.8 7.1 |
| Engine lifespan, km | ~350 000 |
Disadvantages of the M21D24 engine
Long-term overheating of this diesel engine causes cylinder head cracks;
When the glow plug control unit malfunctions, the engine does not start;
Frequently, the lubricant pressure decreases and the oil supply hoses to the radiator crack;
Keep an eye on the timing belt’s condition because it can stretch, jump, and cause phases to go off course. Involuntary starter engagements can occasionally occur when driving through traffic.