View Full Version : Soundproofing NP DiD

nev smith
16-09-08, 02:02 PM
Hi All, In another life I had a n/a nissan 4.2 diesel which was very noisy under load. I put dynamat under the carpets and bonnet and it was much better. I now have an 2006NP and although the difference in power and ride is amazing, I must confess that the diesel noise becomes very tiring on long hauls. Before I outlay another $250 or so, has anybody managed to make the deisel a bit less noisy and if so, how?

Thanking all in advance


16-09-08, 06:18 PM
On the old forum I seem to recall someone spraying a sound dampening coating under the wheel arches. This won't help the donk noise though...

17-09-08, 02:41 PM
i must admit its nice to have a very quiet cabin thanks to the petrol engine but if you need to dampen down the deisel noise all you can do is add this dynamat material to the firewall interior and under bonnet plus a good thick spray of underbody coatings should help abit. i sprayed my under body especially the wheel arches thanks to all those plastic fittings we now have on vehicles was a pain when driving on damp stoney roads, sounded like machine gun fire. the more insulation the better.

17-09-08, 08:35 PM
Is the under body coating readily available from auto stores?

19-09-08, 03:27 PM
Is the under body coating readily available from auto stores?
yes it should be available at auto stores such as Auto-1 etc etc , i bought mine from the Paint shop. its good if you have a compressor as you can buy the matching splatter gun [ about $30 ] that screws onto the underbody can. it works great with no mess to worry about.

20-09-08, 08:01 AM
Do you reckon it made much of a difference in the end and would you do it again if in a similar situation?

green monster
20-09-08, 10:14 AM
I used to have a Tarago (which was a brilliant car) and found it to be a bit noisy due to the lowering and low profile tyres ,so i sprayed the underbody with deadner from 4 cans that just sprayed on ,,it was easy and made a huge difference in reducing road niose as well as protecting,the underbody bits,,worth doing IMHO
Had to include a picture,,,my wife has still not forgiven me for selling that car!!!

21-09-08, 04:21 PM
Hi Nev smith
I own a 2003 Np DID
To lower the noise, which worked I did the following when I brought it in 2003
I purchased an insulation sheet from "super cheap" $60 approx
Removed centre console and and insulated under
Removed both glove boxes and insulated behind.
Unclip the insulation mat on firewall and layed another layer behind.
Removed Plastic cover on engine and added extra and created a flap that hangs down the back over the rear.
I had the sprayed underneath with a rust and sound deading material $250

Result the vehicle and very quiet from diesel rattle and noise levels at 100k are comparable to the EL that i owned before the i brought the PJ

21-09-08, 05:28 PM
Do you reckon it made much of a difference in the end and would you do it again if in a similar situation?yes , any extra under body work will make a big difference, especially when you do it yourself with your own gear. i have seen many new vehicles that have been under body sprayed by certain specialists at high costs of around $600 and i must say not good when you see all the missed areas etc etc. when you do the job yourself you have 100% satisfaction [ true ]

nev smith
22-09-08, 06:57 AM
Thanks for all the info folks.Muzza, your fix is similar to what I did on the nissan and I will give it a go. Are there any traps in removing the centre console and glove boxes/ I havent managed to get my self a manual for a 2006 modle np as yet.

22-09-08, 08:41 AM
The centre console is fairly easy; I have mine (NM) out now for a different project.
Prise the drink-holder out - it has two lugs each side.
Inside there are two screws that will release the gear-lever section. Unscrew the gear knob and 4wd selector knob if you want to take the part right off.

That then reveals the two screws to remove the ashtray section.

You can also then see the front screws for the centre storage bin. Undo those plus the two inside the bin, and it lifts off.

Now you can also get to some those impossible-to-clean locations with a vacuum :-)