The BMW S38 engine is a six-cylinder in-line engine from BMW, which replaced the M88 engine, produced for 10 years (from 1986 to 1996). The S38 engine was based on the M88/3 unit. In pursuit of environmental standards, the first modification of the S38 – S38B35 used a catalytic converter (popularly just a catalyst).
Specifications
| Manufacturer | Munich Plant |
| Also called | S38 |
| Production years | 1988-1996 |
| Cylinder block alloy | cast iron |
| Fuel system | injector |
| Configuration | inline |
| Number of cylinders | 6 |
| Valves per cylinder | 4 |
| Piston stroke, mm | 86 (S38B36) 90 (S38B38) |
| Cylinder bore, mm | 93.4 (S38B36) 94.6 (S38B38) |
| Compression ratio | 10.0 10.5 |
| Displacement, cc | 3535 (S38B36) 3795 (S38B38) |
| Power output, hp | 316/6900 340/6900 |
| Torque output, Nm / rpm | 360/4750 400/4750 |
| Fuel type | 95 |
| Euro standards | — |
| Weight, kg | ~151 |
| Fuel consumption, L/100 km — city — highway — combined |
18.0 8.3 9.6 |
| Oil consumption, gr/1000 km | up to 1000 |
| Recommended engine oil | 5W-30 / 5W-40 / 10W-40 / 15W-40 |
| Engine oil capacity, liter | 5.75 |
| Oil change interval, km | 7000-10000 |
| Normal engine operating temperature, °C | ~90 |
| Engine lifespan, km — official information — real |
— 400+ |
Frequent problems
The main problems of the BMW S38 engine are cracks in the cylinder block, overheating. Cracks form around the threads for the cylinder head bolts. The reasons for the breakdown are oil that has not been removed from the thread, disassembly of the motor. The problem can be diagnosed by the high consumption of antifreeze, the appearance of an emulsion in the oil. The optimal solution is to replace it with a non-cracked block.
If overheating occurs, the problem must be solved quickly so that the cylinder head does not move. Overheating occurs when a thermostat, radiator or pump needs cleaning, or when there is a blockage in the cooling system.
Frequent malfunctions include wear of the elements of the gas distribution system, the complexity and inability to adjust the valve. To solve the problem, eccentrics, guide bushings and valves are changed. Poor performance may be related to the MAF. During the warming up of the car, a whistle is heard, there are frequent leaks of the rear crankshaft oil seal.
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