M42
• First 16-valve BMW engine (DOHC): improved cylinder filling • Timing chain with hydraulic tensioner: reliability and durability • High specific output (up to 140 hp from 1.8 L)
The BMW M42 is an inline four-cylinder DOHC petrol engine produced from 1989 to 1996. It replaced the M40 and was used in the E30 and E36, most famously the 318is. The M42 was BMW's first four-cylinder engine with 16 valves. Later versions received Single VANOS on the intake cam, improving flexibility. Cast iron block, aluminium head, chain-driven DOHC with hydraulic tensioner. Power output was 136–140 hp from 1.8 litres. The engine revved high (up to 6000 rpm) and was fuel-efficient. Common issues include camshaft wear, oil leaks, and aging cooling system. With proper care, the M42 can exceed 300,000 km.