Final Attempt to Get Quiet

After spending the last three weeks in Africa, and being around and in a lot of diesel engined trucks from 200-300Tdi and Td5 trucks, to Toyota diesels and Isuzu diesels from the same era, I can safely say that my truck is 2-3x as loud as anything I experienced.

Part of my loudness comes from the clank/ringing sound I?ve been trying to nail down for the past year. But in general, my idle noise is simply much louder than any other truck I know of.

This means that all my work to quiet the cab does nothing?unless I could find some way to quiet the noise actually coming from the engine bay. Dynamat does not do it. Carpeting and MLV mats do not do it. I can say that these things quiet the cab itself. They reduce rattles and echo, but in a very real way, it just serves to point out how much noise is coming from through the bulkhead from the engine.

But looking at my Range Rover and Disco, I wonder why I can not find the type of thick rubber matting you see in the engine bays of modern vehicles? I think this is my last resort, I just can?t seem to find stuff that I could use in the engine bay. Maybe I?m reading wrong, or not recognizing what I?m looking at on internet images? Any thoughts on really focusing sound muffling efforts on the engine would be appreciated.

Have you wrapped the exhaust down pipe? Made a big deference on mine.

What do you have in the engine bay? There is a genuine bonnet mat. I would use that with some sound absorbing headliner under it. On my 110, I also have seals alongs the sides of the bonnet to the wings.

Thanks, both, I had actually thought of both of these things, so I'm curious about:

1. What/how to wrap the exhaust? Does the simple "tape" stuff do anything, or are you referring to something more?
2. The hood liner is in good condition, but I wonder if some insulation underneath might help -- Dynamat?
3. What/how do you do the seal on the bonnet? I have a little bit of foam tape type of stuff just to help with a rattle, but I've been wondering about doing a full treatment.

Linking a similar thread here: https://nas-row.com/showthread.php?t=624

If your idle is louder than normal you may have a IP that is compromised. What I’ve learned is that the IP cam will deteriorate from wear due to bad fuel. Once that starts there’s no coming back and one sign is loudness and the other is shards of steel peeling away that can be found behind the fuel solenoid. Eventually the shards will interfere with the spring inside the solenoid and cause the solenoid to not function. You’ll know when this happens as the truck will not turn off. Fun stuff.

Talk to Ken at https://store.secondskinaudio.com/
He knows Defenders and he definitely knows sound suppression.

Red90 said:

On my 110, I also have seals alongs the sides of the bonnet to the wings.

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Ooo I never thought of that. I occasionally get a rattle there too...

Something like this?
https://www.homedepot.com/p/Frost-K...ular-Rubber-Weatherstrip-Tape-V25BK/202844545

or this

https://www.amazon.com/NEW-Adhesive-Automotive-Rubber-Weatherstrip/dp/B01N0PRARU

I know it gets bad press on these forums but the Dynamat Hood Liner has worked great for me. I've had it on the truck for months, never soaked up a drop of water, and looks as good as the day I installed it.

My truck also has this rubber mat stuck to the firewall that has a silver reflective backing on it. It looks like it has been there since new. It doesn't have it by the heater box, just behind the engine.

I had a roll of Summit lava tape which I had for the Jag header pipes 3inch by 25-30 foot can't 't remember the lenght. But I wrapped from the end of the turbo elbow to the first joint where it bends down. I did it more for heat transfer but it also took some of the pinging noise away. It's been on for five years and held up pretty good gets cover in mud but washes off good. Also have a Wright's off road mat and Dynamat foam on the bonnet. But my 2hundy has also been a quiet runner. BIGGEST benift is soft engine mounts.

Roverman2010 said:

Have you wrapped the exhaust down pipe? Made a big deference on mine.

Click to expand...

After reading this, I wonder if the reason I've heard people say the 300tdi is quieter is due to exhaust routing? The 200tdi downpipe is on the rear of the engine while the 300tdi dumps by the front.

I bought an engine compartment liner, in sheets, that had a lead layer in it. Friends who have rode in my D90 300Tdi are amazed at how quite it is.
Here's some made for the engine compartment that was not available when I converted mine. These have lead.
http://www.nkgroup.co.uk/product/vehicle-acoustic-engine-blankets/

The transmission tunnel on mine is also from an NAS automatic and has a thick layer of factory rubber insulation over it as well.

Look up a company named Soundown.
You can buy their stuff on Amazon, @ yacht chandlery's etc.

They specialize in reducing the scream of big marine diesels being run a few hundred rpm under redline in big yachts. They sell their products in sheets/rolls. I have glued the material in place with 4200.

This is all good info, and it confirms a lot of the little ideas I've been thinking over. After rereading some other threads, what you all have said here, and the Sound Deadener Showdown site, I've started testing some materials.



I went to a place not far from here that sells nothing but different types of rubber mats. I found an 8mm recycled rubber mat that is flexible and that, according to the owner, is what people use specifically for sound deadening in multi-level apartments, etc... I also found a 1/2" thick closed cell, black foam rubber, and I am currently testing both of these in my oven to see how heat resistant they are. Both of them are oil and water resistant, and according to the Sound Deadening Showdown site, this is the type of thing that really makes a difference when it is decoupled from the surface, etc....


My approach here will be to use layering, and to test different stuff over the next few weeks to see if I can get some results.

AdamSanta85 said:

Ooo I never thought of that. I occasionally get a rattle there too...

Something like this?
https://www.homedepot.com/p/Frost-K...ular-Rubber-Weatherstrip-Tape-V25BK/202844545

or this

https://www.amazon.com/NEW-Adhesive-Automotive-Rubber-Weatherstrip/dp/B01N0PRARU

I know it gets bad press on these forums but the Dynamat Hood Liner has worked great for me. I've had it on the truck for months, never soaked up a drop of water, and looks as good as the day I installed it.

My truck also has this rubber mat stuck to the firewall that has a silver reflective backing on it. It looks like it has been there since new. It doesn't have it by the heater box, just behind the engine.

Click to expand...

I've been wondering about the rattle coming from my bonnet. Turns out the wings are touching the bonnet. Firstly, because the bulkhead I used doesn't have a bolt hole on the front face that would be used to hold the top of the wing down in place! Secondly, because I have diamond plating on top of the wing. So the bonnet essentially rests on the wing! I need to fix this somehow.

The stock hoodliner is in good condition, but now that I'm thinking about it, that doesn't mean it deadens much sound. I think I may pull it out, apply some of the anti-rattle/vibration Dynamat, then sandwich some of the closed cell foam rubber underneath the stock liner.

QUESTION! What would happen if I blocked the transmission tunnel? That is to say, what if I hung a "curtain" of this mass loaded vinyl rubber stuff from the back of the bulkhead, down over the bell housing? Would this be bad for engine cooling in anyway?

RBBailey said:

I've been wondering about the rattle coming from my bonnet. Turns out the wings are touching the bonnet. Firstly, because the bulkhead I used doesn't have a bolt hole on the front face that would be used to hold the top of the wing down in place! Secondly, because I have diamond plating on top of the wing. So the bonnet essentially rests on the wing! I need to fix this somehow.

The stock hoodliner is in good condition, but now that I'm thinking about it, that doesn't mean it deadens much sound. I think I may pull it out, apply some of the anti-rattle/vibration Dynamat, then sandwich some of the closed cell foam rubber underneath the stock liner.

QUESTION! What would happen if I blocked the transmission tunnel? That is to say, what if I hung a "curtain" of this mass loaded vinyl rubber stuff from the back of the bulkhead, down over the bell housing? Would this be bad for engine cooling in anyway?

Click to expand...

Also on the hood, do you still have the two rubber bushes at the hinges?

Noisekiller in the UK sell not just the interior gear but also sell engine blankets. Just don't think I could cover a V8 with a blanket. https://nkgroup.glopal.com/en-US/p-2280/land-rover-full-soundproofing-kit.html

Like Rocky mentioned, the plastic liners for the hood hinges wear out !
They are cheap & easy to replace and a HUGE source of noise if they are worn.

Viton said:

Like Rocky mentioned, the plastic liners for the hood hinges wear out !
They are cheap & easy to replace and a HUGE source of noise if they are worn.

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Been wondering about that, although I know for sure that the current rattle is coming from the rub against the wing top.

RBBailey said:

Been wondering about that, although I know for sure that the current rattle is coming from the rub against the wing top.

Click to expand...

On the bonnet rear corners, by the bulkhead, lift up and down.
If there's movement, there's noise.

AdamSanta85 said:

Ooo I never thought of that. I occasionally get a rattle there too...

Something like this?
.

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There are generic car door seals that slip onto the lip.

Self adhesive “ D ” shaped rubber seal. Works fabulously.