My c240 has begun making a whining sounds when the car idles and when I accelerate, what causes this?

 

Locate the noise if it is from the front of the engine or transmission. Common idler pulley, a/c compressor pulley, alternator. The trans if making the noise could be due to coolant leaking into the tranny due to faulty Valeo radiators. This was not uncommon but will typically be followed by odd shift quality/noises/shudder. If the engine, you can use a long screwdriver to the ear and rest it on each device (not the moving pulley) and carefuly listen for the component. The loudest similar sound will be the problem.