Engine BMW M40B18

Engine BMW M40B18

The BMW M40B18 four-cylinder engine replaces the old M10. It has hydraulic lifters, so the valves do not need to be adjusted as often. Here, unlike the six-cylinder BMW engines of that time, a timing belt is used. If this belt breaks, the valves will bend, and this will already entail large investments. The volume of the M40B18 engine is 1796 cc. Engine power – 113 HP For the E36 body, it differed only in the injection system. The cylinder diameter, like that of the 1.6-liter engine, is 84 mm, and the piston stroke is increased to 81 mm.


Manufacturer Steyr Plant
Also called M40
Production years 1987-1994
Cylinder block alloy cast iron
Fuel system injector
Configuration inline
Number of cylinders 4
Valves per cylinder 2
Piston stroke, mm 81
Cylinder bore, mm 84
Compression ratio 9
Displacement, cc 1796
Power output, hp 113/5500
Torque output, Nm / rpm 162/4250
Fuel type 92
Euro standards
Weight, kg ~132
Fuel consumption, L/100 km
— city
— highway
— combined
Oil consumption, gr/1000 km up to 1000
Recommended engine oil 5W-30 / 5W-40 / 10W-40 / 15W-50
Engine oil capacity, liter 4.0
Oil change interval, km 7000-10000
Normal engine operating temperature, °C 90-95
Engine lifespan, km
— official information
— real


Frequent problems

The characteristic problems of BMW M40B18 engines are: knocking, floating revs, dips when gaining speed and overheating. Each problem has its own reasons. Engine knocking can be caused by wear on the camshaft, hydraulic lifters and rocker arms. The condition of the parts must be checked.

Engine BMW M40B18 under the hoodFloating revolutions arise due to a breakdown of the mass air flow sensor, there may be an air leak. Carefully inspect the engine, check the mass air flow sensor, assess the condition of the KXX and the throttle valve, check the lambda probe. Poor camshaft rotation may be causing the problem.

If jolts are noticeable when picking up speed, most often you need to clean the injectors. If the engine overheats, there may be several reasons: it is necessary to inspect the pump, thermostat. The reasons may lie in the radiator, pipes of the cooling system.

If there are problems with the fuel pump, damaged wires, coil and spark plugs, the engine will not start. The timing belt can cause trouble.

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