DBS might not activate during emergency braking situations, potentially leading to longer stopping distances.

Misfires can be caused by ignition coil or spark plug issues, leading to rough idling and poor acceleration.

Turbochargers in BMW 640i can sometimes fail, resulting in reduced power and increased exhaust smoke.

BMWs are known for cooling system issues, such as radiator, water pump, or thermostat failures, which can lead to engine overheating.

Common in BMW engines, oil leaks can occur from the valve cover gasket or oil filter housing gasket, leading to low oil levels and potential engine damage.

This can cause stalling, poor performance, and difficulty starting the engine.

Problems with the timing chain can lead to rattling noises and, if severe, can cause significant engine damage.

Issues such as rough shifting or transmission failure can occur, especially as the vehicle ages.

BMW 640i models may experience problems with electronic components, such as sensors, control modules, or wiring harnesses.

Direct injection engines like the one in the 640i can suffer from carbon buildup on intake valves, leading to performance issues and rough idling.

DBS may fail to activate properly due to sensor or software issues, leading to ineffective emergency braking assistance.

Misfires in the 6-cylinder engine can be caused by faulty spark plugs, ignition coils, or fuel injectors, resulting in poor performance and fuel efficiency.

The 640i's turbocharged engine might suffer from turbo lag, boost leaks, or failure of the turbocharger itself, affecting overall power and acceleration.

The timing chain in the 2018 BMW 640i may stretch or fail, leading to poor engine performance, noise, or even catastrophic engine damage if not addressed.

Common in BMW engines, oil leaks may occur from the valve cover gasket, oil filter housing, or oil pan gasket, causing potential engine damage if oil levels drop too low.

Issues with the water pump, thermostat, or radiator can lead to overheating, which is detrimental to engine health and performance.

A failing high-pressure fuel pump can cause starting issues, engine stalling, or a loss of power under acceleration.

Modern BMWs are equipped with complex electronics that may fail, including sensors, control modules, and wiring harnesses, leading to various drivability issues or warning lights.

Direct injection engines, like in the 640i, are prone to carbon buildup on intake valves, which can lead to rough idling, poor acceleration, and reduced fuel efficiency.

The automatic transmission in the 640i may experience rough shifting, slipping, or failure, impacting drivability and performance.