On the underneath side of my engine cover is a very soft fabric (like a very loose weave kind of insulation) that was heat sealed to the underside of the cover. What purpose does this fabric serve? Can I replace it with something else (mine is deteriorating)? Should I just try the dealer?

Ok, I went to the dealer. The insulation, which is used to keep the plastic cover from melting as a result of engine heat, is not sold separately. I'd have to buy the whole plastic cover with new insulation. I'd rather not. But the existing insulation is sloughing off all over the engine compartment. So any suggestions about where I can get the insulation or something similar?

 

It's purely sound insulation

 

Well that's good news. Thanks for your expeditious reply. The guy at the Mazda parts counter had me convinced it was a thermal shield to keep the plastic from melting as it is mounted directly over the valve train.