I have a '92 525 with 165K. Recently I started hearing a clicking sound from the engine area that is louder when the engine is first started (cold) and gets quieter as the car warms up 2-3 miles until it's finally gone. It seems to occur in conjunction with pressing the gas pedal and accelerating. Taking your foot off the gas will stop the noise. I don't believe it's anything related to tires, wheels, or transmission. Depressing the gas pedal in neutral will not cause the sound. It seems to occur when the engine is under the stress of acceleration. It's a definite click that increases in cadence as the vehicle accelerates. I'm thinking it's some type of solenoid that is supposed to open and close, but is worn and now causing the noise. Any ideas?