When I shut down my late 2011 2L Diesel, all goes quiet for 7 seconds or so and then the front gives out this loud sigh... like a mini fog horn. Perhaps the front right hand side. I also notice that after a day or so, upon starting the car, the front seems to me to rise for a little longer than before; but I'm not so sure esp as the sigh/foghorn is intermittent. The foghorn problem is my main puzzle. Has this happened to anyone & is there a likely cause that jumps to mind, please? Thanks, Eddy