My wife's SLK350 makes a chirping noise for 3 seconds every 30 seconds for a matter of hours after switching off on a hot day. The noise stops if you re start the engine and then switch it off. The noise is coming from somewhere near the bottom front corner of the engine in the area near the air con compressor but defies definite location. It refused to make the noise at the dealer and they watched the video I had shot of the noise and even offered to send it to Germany if needed. They think it is the ABS pump re priming itself because of excess heat. Any ideas? Thanks