engine and drivetrain Sound deadning

[mhoffperson]

Some dumb questions, I've done some searching but I couldn't answer all my concerns. I got a bunch of the original Dynamat left over from a friends Hot Rod project that I plan to use.

So before I pull my carpet to replace it I have a Dynamat question. I keep reading about getting the old sound deadning out with heat guns or dry ice. If the stuff is already there shouldn't I just leave it in place or put the Dynamat stuff right over it? Secondly, I read that people put the dynamat on the door right under the upholetered door panels. Is that prefered? I was thinking to put it on the inside of the door itself since I have the windows out at the moment. Finally, I was planing to cover the firewall, transmission tunnel and doors only, is there much noise transmitted through the floor pans and rear trunk (I was going to put foam pieces under the rear seat)?

Thanks in advance for any advice.

[richk98]

Once you pull the carpet you're likely to see why so many pull the old sound deadening and replace it with dynomat or something similar. It has a tendency to attract moisture, become heavy with dampness and cause rust. At least that's what seems to have happened to some of my floor pans. You can be the best judge of the scope and effort once the carpet comes up. You'll be amazed and what you'll find under there.

[Chris_B]

My experience is that the factory sound deadening is hard as a rock and difficult to remove after 30 years. I have not seen any rust under the factory sound deadening in any 02, but I have mostly seen CA cars with little or no rust overall.

I used Accumat in my car, which is similar to Dynamat (but a bit less expensive when I did my car 5 years ago...). I applied it to the inside of the door skins, to the back of the door panels, inside the rear quarter panels, under the console, under the back seats, and in the trunk (fully lined the top and sides of the trunk).

My 02 sounds like a modern car WRT to wind and road noise. I think it would be even better if I applied sound deadening to the roof, but I am waiting until I replace the headliner. Many who have had a ride in the car have remarked on how quiet it is.

I am not sure I would recommend this to anyone interested in strict originality. The aftermarket sound deadening could be removed, but it would be a big job.

[gwb72tii]

we just did this for benetton's 73 project, and i can tell you there was a fair amount of rust up front on the driver's side once we removed the factory stuff. there were even two pin holes caused by the rust we repaired, and then used por-15 to make sure it didn't rust again.

i've taken the stuff out of two 2002's and never run into any significant difficulty removing the factory stuff.

also, the round floor pan plugs on both sides, front and rear (4 total) in the passenger compartment tend to leak over the years. these plugs i believe were for allowing the primer to exit the passenger compartment when the body was dipped in the primer. if i were you i'd make sure they are sealing properly. again this is one area of rust we ran into on benetton's car, which we thought was rock solid (it is) with no obvious signs of rust anywhere.

[richk98]

When I pulled my carpet I found that in addition to the asphalt-like sound deadening, there were press board like panels with foam backing that covered the driver's, passenger and parts of the tranny tunnel. The press board was slightly worn through, damp, moldy and heavy and there was significant rust through in the driver floor pan area that may have started from under the car but wasn't obvious until the "insulation" was removed. There were asphalt pads under these as well but they were not in good condition and no longer functional.This is in an 02 that has spent it's entire life in California. After 12 hours and trying different methods, I found that warming the asphalt with a heat gun and using pneumatic scrapers and wire rope brushes on an angle grinder made it simple. Probably would have taken 3 hours in total had I started with these tools rather than trying elbow grease for as long as I had. I'm glad I removed it all. Yes it was a lot of work, but I am now confident that my floors have been properly repaired, POR'd, and sound proofed.