Never heard of an engine blanket.

it might be worth removing the carpets from where the noise appears to be worse and have a look see how good or bad the cars insulation is, might be easier to insulate from inside the vehicle.

I have effectively improved the soundproofing on two of my family's cars recently, C2 VTS and Aygo suffered from really bad road roar, C2 was unbearable especially on its OE Michelins, now thankfully replaced with some decent rubber..;)

Upon investigating there is no proofing whatsoever in the boot or around the rear wheel arches of either vehicle just a thin plastic moulding or boot cover, i have cut to size and lined with insulation and both are now considerably quieter for this, the booming has gone and rain spattering on the wheelarch doesn't deafen any more.

Couple of hours did each thoroughly, and in both cases the front end and engine wasn't really a problem, the majority of noise has gone now the rear is subdued.

Proper car insulation is cheaply available from the usual auction site, both loose lay for glueing in if needed and self adhesive.

Edited by gordonbennet on 28/08/2012 at 17:16

A lateral sugestion -- how about foam ear pellets, of the type that motorcyclists use to cut down wind noise fatigue? These still enable you to hear fine, they just reduce the general racket.