525i: beeps from the engine

Really would appreciate anyone that can help.

I get 3 beeps rsequentially (sharp noises) from the engine whenever the engine is running. It has no specific time but occurs each time the engine is warm. Noticed this on a long journey after topping my engine oil. No overheating though.

Thanks.

mine did that too and it was the hydraulic tensioner for the a/c belt.I replaced it and it started doing it again.I used a manual belt tensioner from a Porsche 944 to replace the BMW one.