So, my car was parked in the middle of a city for a few days, not a barnyard or anything like that, but nonetheless some mice decided to get into the engine bay and rip up the insulation.<p>This includes two pieces: the insulator attached to the underside of the hood, and a piece made out of the same material (a black synthetic substance with some sort of padding inside it - looks almost like cotton swabbing?) that stretches around the back of the engine bay, behind the engine. That piece seems to insulate between the engine and the body of the car, including, I guess, whatever electronics are built into the area in front of the dash/under the windshield/wipers.<p>Now I have a couple of questions I hope people could help me with:<p>1. Are these parts absolutely necessary? Searching the archives I see Shagginwagon, Bender, R drivers etc. experimented with ripping the insulation and weatherstripping out of their engine bays in order to make their cars go faster... As they noted back then, the engine is louder without the insulation but otherwise no apparent immediate difference. Obviously the hood gets hotter too. Is the piece of insulation behind the engine protecting the ECU or other components from heat damage? Will they get fried without it?<p>2. Does IPD or anyone make aftermarket S60 insulator pieces that are not attractive to rodents? All synthetic or something? Maybe lightweight performance hard foam? I don't care if they're louder than stock, I want something that vermin won't be attracted to again... and I also don't mind the occasional performance mod <IMG NAME="icon" SRC="http://www.vwvortex.com/vwbb/biggrin.gif" BORDER="0"> <p>The hood insulator is trivial to remove/install, but the insulator behind the engine requires a bunch of stuff to be disconnected to get at it. Might even require dropping the engine. Checked with the nearest dealer and local bodyshop and neither of them could find a schematic from Volvo on how to go about replacing it. Right now it looks like a question of just starting to take stuff apart until you can get it on. Will check with another dealer I know pretty well who often seems a bit more on the ball... they might have a procedure for it.<p>As far as I can tell the mice didn't chew on any wires, everything looks fine and the car registers no problems - in fact it's driving very well right now. So no problems on that score.<p>The part numbers in question are 8641171 and 8641898, supposedly 8641898 is replaced by 30755360 now, if that helps.