Will a bonnet noise deadening mat really help

[IslandDefender90]

Does anyone know if a bonnet noise deadening mat will really make a difference is the engine noise? I would have to ship it internationally which is expensive so want to be sure it is worth it. 

[Maverik]

I've got a standard 300tdi type black matt thing, had it for years and in my opinion, yes it reduces engine noise in the cab. 

Noise is a difficult topic, it takes lots of little fixes to really have an effect, but I would recommend bonnet insulation for sure 👍 

[Bowie69]

Also quite subjective, for some the engine rattle is the worst, others, the gearbox.

Also depends on the vehicle, a van will be louder than a CSW or a soft top.

[Snagger]

It will make a difference when you have the vent flaps or windows open.  With those shut, the only sound proofing that matters is what you have inside the cab, mostly on the bulkhead and floor, but don’t underestimate the noise from the tub floor, wheel arches and any hard top sides or roof.  The top of the foot wells allow a lot of noise in, and I found some benefit from cladding the exterior of the heater housing as that is made of thin sheet steel and is a good echo chamber into the dash.

I found absolutely no benefit from the (expensive) lining of the entire engine bay, but some medium density foam sheet on the underside of the seat box did knock down transmission noise considerably.

[Nonimouse]

I have a 300tdi engine cover on my 200. That makes a big difference. I took the mat on the underside of the bonnet off (for repair and clean) made not a jot of difference. This is a DIscovery

[Snagger]

The engine covers do help reduce the tappet and injector noise, reducing the ticking sounds in the cab.  I did the same, fitting one to my 200 in the 109, after chopping bits off to clear the Defender manifolds and turbo.

[IslandDefender90]

Thank you everyone! Such helpful info. So from the sounds of it, it will not be cost effective for me. We are on a Caribbean island with the windows down always and will be converting to a soft top. I am trying to dampen the engine noise a bit to make it more enjoyable to cruse the beaches. I will try the foam trick in the cab first and see how well that does

[Snagger]

As I said, it does make a difference when you have the windows open (because it reduces external noise quite a bit generally).  It’s not worth lining the rest of the engine bay, but the rubberised plastic and foam engine top cover from a compatible model will also make a difference.  Most of the noise is from inside the vehicle, though, so it’s s worth doing the bulkhead and floor internally.

Given your location, I think what may be your best option is to have the inside of the cab and the underside elf the bonnet sprayed with Lizard Skin or similar, so that you don’t have matting or foam holding moisture and salt against the body panels.