Underhood insulation missing, should I replace it???? - PeachParts Mercedes-Benz Forum

jay3000 · #1 05-05-2003, 12:11 PM

What is it's purpose??? Sound damping, or heat shield, or both???

Is it worth the money, time, and effort to replace it??

If so, should I use dynamat, or something similar???

Thanks,
Jay

haasman · #2 05-05-2003, 12:14 PM

Jay

Yes it is worth it, it does reduce noise and temperature. If you do a search you will find many postings regarding which glue, how to's etc.

Keep us posted,

Haasman

#3 05-05-2003, 08:13 PM

My opinion is to replace it as it reduces sound and serves as a heat barrrier for the hood(i.e.paint). Here is a post I found and saved as a word document and it was great. An extra set of hands helps a lot and use plenty of adhesive. Take it from me, be sure to cover the engine compartment and fenders to keep the adhesive where you don't want it as it is a PIA to get off. By the way I spent the little extra and got the pad from the dealership.

The post (not mine but it was good)

Replacing your Hood Pad
By Dan Penoff

1. Raise hood to full vertical position
2. Find junky sheet to cover whole front of car/engine compartment
3. Get hard plastic scraper (a windshield ice scraper does very well, and I have no current use for one where I live anyway!) and start scraping
4. When you get the adhesive see if the supplier has 3M Adhesive and Decal Remover. This is really nasty stuff but will not harm automotive finishes other than to strip the wax off. Very flammable as well, so don't do this around the water heater or enjoy a Macanudo while applying it. Soak a shop rag in the stuff and get it all over the remaining gook from the old pad. Since it's mostly naptha it does evaporate quickly, so work in small areas. Once the remains of the pad are softened up scrape away! Don't obsess about complete removal, as you won't get all of it off. Some people use metal scrapers such as putty knives which are pretty dull, but I prefer not to. My concerns are that scratches in the finish could possibly rust from moisture trapped in or under the pad. Certainly don't want my hood rusting from the inside out!
5. Once all this is done carefully apply the adhesive. I say carefully since it will attack painted finishes on you car, so spray close to the hood and avoid any overspray. I like to spray a 4"-6" section across the top (front) of the hood with a corresponding application to the pad in the same area. Let the adhesive set up the prescribed amount of time.
6. Get the pad lined up and stick it on in one corner. Line it up on the other corner and make sure it's in place, then press it down. Now the pad will be hanging curtain-like from the leading edge of the hood.
7. Apply the remaining adhesive to the hood and pad and press it into place after it sets up. I have a brayer (a hard rubber roller used for laminating) that I like to use to go over all parts of the pad, making sure it's stuck on well. Leave it in the vertical position for an hour or so, then you're done!

haasman · #4 05-05-2003, 08:21 PM

Welcome git0!

Excellent advice. I would add- use 3M automtoive products: HD spray adhesive and if necessary the adhesive remover.

I have done at least three underhood pads. The cars were always quieter and in the summer, the hood paint seemed to be cooler.

Keep us posted,

Haasman

erubin · #5 05-06-2003, 02:34 AM

I am missing the hood pad from my 72 SL for as long as i've known it the car (20+years). The paint does not degrade sooner on the hood then on the body so for me that is not a concern. as far as noise goes, roadster are noisy so i don't blame it on the pad, with a diesel i would think otherwise. One day i'll put in a pad because it should be there but i doubt it'll make much diference at all.

maheath · #6 05-06-2003, 11:20 AM

I've heard that another function of the hood pad is to smother an engine fire.

jay3000 · #7 05-06-2003, 11:23 AM

Quote:

Originally posted by maheath
I've heard that another function of the hood pad is to smother an engine fire.

I don't know about that.. Looks like it would just be FUEL...

Flash Gordon · #8 05-06-2003, 04:39 PM

Another important function of the pad is keeping the engine area warm for a longer time in the winter. This can also generate the opposite result in the summer by keeping the engine area hot for a long time. I usually open the hood in the summer after I get home. Remember, heat is one of the worst enemy in the engine area