Hello folks!

I've been away for several months, but I'm happy to be back.

After chasing some water leaks that kept making a pool in the rear of my car floor panels, I decided to remove all the carpeting and have a look at the insulation and floor condition.

To my horror, the insulation is all rotten and some rust spots started forming in the floor panels. I also noticed the firewall insulation is starting to fall off

I already stopped the water leak (which came from the front windshield) and removed all the floor insulation. In the mean time I got some carpet pieces under the factory carpets to help with the heat and the noise. However I want to do some serious fix on this.

Now, I know most people say Dynamat is the way to go in this case. However, I'm not very attracted by this idea. First, I noticed that somehow water got between the original insulation and the floor panels which accelerated the rust. Since the original insulation was sticked to the floor, just like Dynamat is installed, I'm afraid the same will happen eventually. Second, I'm on a budget, so its very unlikely that I will spend $400+ on insulation.

I did some research and might have found a cheaper alternative. First you get some aluminized foam roof insulation. Then you get some high density fiber carpet insulation. The ides is making a compound carpet made out of three layers of material (foam, carpet, foam) leaving the aluminized surfaces facing outwards of the sandwich.

Once you have made the compound insulation, you paint the inside of the floor panels with Gravitex Plus. This is a type of high density compound used to cover under body panels to protect them from stones and gravel. This product avoids corrosion and reduces panel resonance.

After the painting, you cut the compound insulation to the desired shapes and glue them with contact cement to the car floor. The key here is using contact cement only in the corners and some little spots in the center, just in case you have to remove the insulation later down the road.

Bottomline, the Gravitex will reduces body resonance, the compound insulation will reduce heat transmision and dampen noice and since this is not glued to the car like the original insulation or like Dynamat, you can remove it anytime you need to do body work or if you feel you need another layer of Gravitex.

Now, any thoughts guys? I'd really like your input?

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1982 W123 300D NA Euro, 300K Miles, 4-speed manual, 3.46 rear diff, early W126 front brakes, Penta rims with 205/60R15 FH900's, custom fitted (by me) audio system, more to come into the money pit... Soon to be installed: Bilstein HD, R107 front discs and 4-piston calipers, HD Suspension springs, wagon front swaybar.

Here are some pics of the materials...

You can see the high density fiber carpet, the roof insulation foam and the gravitex. I also attached the gravitex technical data pdf.

Attached Thumbnails

     

Attached Files

gravitex.pdf (14.4 KB, 564 views)

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1982 W123 300D NA Euro, 300K Miles, 4-speed manual, 3.46 rear diff, early W126 front brakes, Penta rims with 205/60R15 FH900's, custom fitted (by me) audio system, more to come into the money pit... Soon to be installed: Bilstein HD, R107 front discs and 4-piston calipers, HD Suspension springs, wagon front swaybar.

Interesting. I'll keep it in mind since my insulation on my driver's side panel was completely drenched in motor oil

I hope you're planning on putting por 15 onto those rust spots

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-Typos courtesy of my mobile phone.

What is this "insulation" you're talking about? I take out my floor mats and I'm down to a painted hard surface.
I will say that investing in POR-15 for rusted areas is worth the expense.

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1982 240D automatic
Odometer quit at 307K...about 325K now

adam, I haven't seen POR-15 down here. However I found something that its called rust stabilizer. It come in metal cans just like paint. It's a clear substance that when applied to rust, turns the rust color to purple. It's meant to chemically disrupt oxide, leaving bare metal underneath the purple layer. Once the chemical reaction is done (about 5 minutes) you flush the parts with water and clean them with a wire brush. After that, you're ready to paint. I'll get the specs to share them with you. I think this is the same as POR-15.

herring, the insulation is a hard layer of material that is glued to the floor of the car. You're right, its painted. Its right under the molded carpets. In the front floor panel, is about 3/8" thick. You can notice this if you lift the parking brake cable that goes through the driver side. It will look like you have a "double" panel there. In the rear its about 1/16" thick.

Anyone has a picture of this? I didn't took pictures when I removed mine...

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1982 W123 300D NA Euro, 300K Miles, 4-speed manual, 3.46 rear diff, early W126 front brakes, Penta rims with 205/60R15 FH900's, custom fitted (by me) audio system, more to come into the money pit... Soon to be installed: Bilstein HD, R107 front discs and 4-piston calipers, HD Suspension springs, wagon front swaybar.