BMW 4-CYLINDER THERMOSTAT SWAP
It’s almost twenty years since the all-new BMW N42 engine appeared in the facelifted 3-Series saloon and new Compact in September 2001. This unit was highly complex and made a big step forward for the Bavarian company – its immediate predecessor was the single-cam 8v 1.9 M43TU that was a development of an engine launched in 1987 – but the new N42 really was futuristic. All alloy, 16-valves with variable valve timing and inlet valve lift, it used an alloy block with the front timing cover integral with the block.
The complex timing chain and tensioner arrangement with two Vanos solenoids meant there was no room on the front of the block for either a water pump or a thermostat, so BMW remotely mounted a complete power steering pump and water pump unit on the exhaust side of
