While overall super happy with my 2.0TDI, I hear too much the engine noise. It is not the end of the world, but it grinds me down on long journeys. And particularly when I compare with the Volvo S60 I used to drive. So I started researching how to make it quieter. This post is documenting what I have done and I will do. And in case anyone has ideas, just add to it.
1.- Ideas to get references:
The superb III owners has a very long thread (23 pages and counting) on the topic. It made me wonder that maybe the mk2 is better in this regard.
This YT channel has interesting material. Example video: Sound Deadening a Car Where It Actually Makes a Difference!
A bit off topic, but this video How Much Weight can you REMOVE from your Car? (Weight Reduction) opened my eye to the insane amount of insulation material you can find in a BMW 3-series. I do suspect you won't find the same in a Skoda.
Insonorizar Coche a Nivel Profesional | El Secreto de los Coches de Lujo. What would it take to go full in into making a car quiet (in Spanish)
2.- My plan. So I won't go a fully deep as the pro-video at the end (though I may consider it), but I do plan on making the 20% that may give 50% of the return. Bonnet insulation, trunk insulation, and a quick change in the floor mats.
3.- Progress so far:
ACTION 1: In the trunk, I put sound absorption under the spare wheel. There is very little sound dampening, but I made a quick fix. I got approx 1x1m sound absorbing foam, made a hole, and threw it under the wheel.
This was super quick to do, and about 14 EUR for the foam, if I recall correctly.
RESULT: My goal is mainly to reduce engine noise, so it had no impact there. But this was super quick and easy. Interestingly, the back feels way quieter. Right after doing it, I game me the impression that a chunk of the car in the back was missing, because I didn't hear as much noise.
RECOMMENDATION?: Yes do it, because it is super fast. Also, it can be undone, there is no glue involved.
Picture of the kind of material I am taling about.
Picture of the wheel space BEFORE I put the foam. I have no after pictures, but basically anywhere you see metal sheet (brown), now is covered with foam.
ACTION 2: INJECTOR CLEANER. I read it may help the enginge run better and be smooother. I had to do it for maintenance regardless.
RESULT: No difference in sound.
RECOMMENDATION? For the injectors, and also it is quick and cheap. But no noise change at all.
ACTION 3: NEW CARPETS, AND STICKING NOISE ABSORPTIONUNDERNEATH. So I got new mats, because the previous ones were too old. These are rubber, as they fit better how I use the car. Happy with the mat, and decided to stick a 1cm thick sound foam underneath. It took me some time to cut it to size.
RESULT: Less vibration through the feet. A bit less of noise probably.
RECOMMENDATION? Optional, but I do appreciate a bit less of vibration. Also, super easy place to add noise insulation on the interior, as one has perfect access.
ACTION 4: CAR BONNET 1. ALUBUTYL LAYER
So now heading straigth to address my main problem with engine noise. This requires a bit more time, and I am still working on it. First, I removed the headshield in the car...
and there is the heat shield, that starts to show its age (14 years), not looking flexible and letting go some powder. Also, the bonnet metal sheet has zero sound dampening or insulation. I don't know if the heat shield is supposed to absorb noise, but I do not think it is in any condition to do so effectively.
So yesterday, I started to apply alubutyl layer, and sticking it. I am only 40% done, because I ran out of time and the surface is complicated with all the different crevices. This is a bit of a tiresome job.
RESULT: So far, inconclusive. I can't sense a difference. but I am not done....
FUTURE ACTIONS:
ACTION 4: CAR BONNET 1. ALUBUTYL LAYER, COMPLETE IT. Maybe in a couple of weeekends I will have time, and then...
ACTION 5: CAR BONNET 2. SOUND INSULATION LAYER. I will add a second layer of sound insulation foam. From the videos, alubutyl mainly prevents vibration on the metal, and the job of the sound foam is to absorb the noise. So both work together better. I will report back with pictures on both processes.
ACTION 6 - MAYBE: Figure out where else in the engine bay can alubutyl and sound insulation be applied.
ACTION 7 - MAYBE: Put noise absortion in the front wheel wells.
UNLIKELY ACTIONS:
I won't go any deeper on a DIY mode (no door panels, removing seats and carpet, dismounting pillars,...)
If I am not satisfied, I may go to get a professional sound insulation, the kind that
removes the seats
removes carpet
removes car panels
...and adds insulating material throughout. Like the Spanish video I link above.
Any ideas on cost?
If I am not satisfied, make peace with it. Or save a lot of money and buy a Lexus.
That is my plan. Any ideas, welcome! I will report back as I make progress.