My ML 270cdi developed an air leak a month ago. More of a whooshing from under the hood. Took it to my local mechanic who smoke tested it and found the inlet was leaking like a sieve and a couple of flaps were broken. I must also add that there was no noticeable lack of power whilst accelerating with the increasing 'whooshing'. Flaps in the inlet removed, cleaned, inlet sealed and re- assembled. Still the same. Turbo clamp to primary CAT was also replaced at the same time. Next port of call was the cat itself which was found to be blocking the exhaust, so contents of said CAT removed and put back on the car. Still no drop in power but the whooshing seems to have increased but now more from under the car. Now I know the 5 pot isn't the quietest of engines but this air whoosh is louder and obviously more so accelerating down a country lane with the window down. Has anybody else here had a similar problem. I'd be grateful for any input. TIA.