Sound and Heat Insulating a
Diesel Hummer Part 2

Insulate Engine Cover Article

Now that the optional floor is complete continue with the rest of the job which is where the Off-Road Comfort version begins.

Layer 1- Use a vibration damping based product. I used Cascade VB2 and VB2HD because I already had it. You can use Dynamat or something equivalent. These are vinyl based sheets containing silica mica and ceramic. There is no odor, like an asphalt based product. Use the heat gun to apply it. It will help melt it and will assist in making it stick to the metal.

Layer 2- Use a Damping/Reflecting product. I used a layer of Cascade Audio VMAX. Dynamat Extreme is similar. This is good stuff. Butylene rubber bonded to thin aluminum. It really does work.

Layer 3- I took the trim panel and glued in an approx. 1" thick piece of cotton shoddy material from the Maybach. This is the blue, cotton based insulator. This was glued directly onto the rear seat trim panel.

You are limited by how much space you have between the wheel well and the trim panel. You should not over-stuff this area as the trim panel will resonate when the truck is at idle. Make sure you do not go too thick. Also, make sure all trim panel retainers will retain the trim panel to the render when done. Test fitting required. You may need to trim a little here and there, but it will go fast.

You will want to fully layer the back wall that divides the interior from the cargo compartment. This wall is made from very thin aluminum and there is a lot of resonance. I might have done 5 or 6 layers of Cascade Audio VMAX in this area. It was extensive. Basically, when you tap on the panel with your knuckle, you do not want to hear or feel any resonance, vibration or echo. That is the rule of thumb that I used. You want the panel"dead" because you are mass-loading it with the aluminum VMAX sheet.
I then attached more of the blue cotton shoddy Maybach material to the back wall. The audio sounds significantly better from just these basic enhancements. The speaker housings I also insulated internally, with more of the blue cotton shoddy material.

After you do the rear of the truck, you can move forward and work on the drive tunnel, the floor, and the engine cover.

I agree 110% with Insulating the Engine Cover. Chuck has a much more effective method with the leaden sheet than what I did. Follow his tutorial.

To begin to strip the drive tunnel, you pull the front seats out. 4 allen head bolts attach the seat base to the floor of the vehicle. If you are a muscular guy, you will have a hard time getting to the bolts. Find a 130 pound soaking wet Ecuadorian mechanic and throw him $20 to loosen the bolts. He can get his hands in there much easier.

Now that you have the seats out of the truck, you can take them to the upholstery shop and have the interior work done.

Starting again from the rear passenger seat area, you will want to carefully pull up the door sill rubber tread material. These literally lift straight out and are held in place with special 3M adhesive. Once the rubber tread material is removed, you can get in there and carefully remove the trim panel retainers that hold the sill trim pieces in place. Be careful that you do not bend the trim panel attachment bolts in the process. Pull the retainer off at a straight 90 degree angle. Take your time. The sill trim panels come off easily. The seat belt trim panel on the b-pillar can be moved out of the way and kept in place as long as you loosen the Philips head screws.

Take off the rear HVAC cover. It is 4 Philips head screws that hold it in place. Put it somewhere safe.

Get a socket set and undo the rear seatbelt receptacle bolts that are located on the drive tunnel. You want to take the seatbelt receptacle arm off. This is the part that you insert the seatbelt into. Then remove the trim panel retainers. These panels will now lift right out of the truck.

I was able to remove the front passenger kick panel and drive tunnel cover WITHOUT removing the dog house by taking my time and gently flexing the plastic trim panel covers.

Do this also on the driver's side. I did not have to remove the plastic trim shift lever cover that is directly to the right of the driver that covers the shift lever housing.

Now that you have these panels out, you can pull up the floor of the truck. Grab the vinyl floor from the rear and roll it forwards. It is held in place with glue. You will probably be suprised to find that the closed cell foam under the vinyl floor is wet and moisture is probablygoing to be present.

Now the real fun can begin!

Right around this time, I started cleaning up the wire loom with zip ties, etc...for the wire runs that go along the side sills / rocker panel area.

Page 4