Rattling noise

I had the same issue with my '05 S40. However it wasn't the suspension. * I had to repace the control arms. The bushings were gone! The problem was still there. * Mechanic said the struts were bad. Replaced them. The problem was still there. * I then started getting the clicking noise when I turned right and it progressively got worse. I assumed it was the CV joint. Replaced that! The problem was still there. * I have now found the real source of the problem. It is the Passenger side Upper Motor Mount. Problem Solved. Real easy to replace DIY. About a 3 on a scale of 10. The motor mount is located next to the coolant tank. Oly 4 screws to remove. Search links on how to replace the upper motor mount. Great details and photos of broken part and details of the typical symptoms. All just as you and I noted. Part cost about $115-$130 online. Using a jack under the motor, you should be able to do this yourself.

The rattling sound may be caused by a bad sway bar link end. To locate mysterious rattles and creaks, if a repair shop cannot locate the sound, a lot of repair shops have a device for pin pointing such noises. It is a headset and wires with microphones attached to clamps, you rotate the dial on the electronic box (which switches to the various microphones) until the noise is loudest, great tool made by a company called Steelman, http://www.steelmantools.com/97222.htm, or http://www.autobarn.net/xxxw-ste97202.html. The Check Engine Light will be unrelated. If the Check Engine light/Service Engine Soon light illuminates while you are driving, the car's on board computer sees a fault in the engines management system that is causing an excess amount of pollutants to be emitted from your car. This could result in engine damage if left neglected. Some problems that can cause the Check Engine light to stay on may take two "drive cycles' to complete before illuminating the Check Engine Light. The computer sees a problem and looks for an identical set of circumstances to occur to confirm that it has indeed seen a problem before turning on the light. A Check Engine light that continually flashes while you are driving is serious and is a sign that the computer sees a problem that seriously risks damaging the catalytic converter which may result in an expensive repair or even may cause a fire! Diagnostic codes are stored in the vehicle's computer and can be retrieved using a scantool that communicates with the computer in your car. We have in our Repairpal website an encyclopedia with in depth articles about computer, and computer control systems, emission and driveability problems. http://repairpal.com/check-engine-light