Hood pad
 

Has anyone tried to replace the hood pad under the hood to protect the hood from the engines heat?
Mine has started to fall apart and is falling in chunks and is about 30% gone in less than a month.

I did mine a while ago. Preparation is very important, as is the right adhesive. A search will bring up lots of info.

Yes. Do some web surfing and get the best price. Try www.***************. I have found their prices to be very good. Order the pad that fits your car. Then, take an old sheet or something that will cover your ENTIRE engine compartment and use a plastic scraper to clean off all the old hood pad, letting all the old junk fall onto the sheet (instead of all over your engine compartment). Then, after making sure that the replacement pad will fit the hood first by doing a preliminary fitting without adhesive, spray some 3M spray adhesive on the underside of the hood, position the pad carefully, and gently press the pad in place. You might want to contact a local MBZ shop to ask which 3M spray adhesive they recommend for doing hood pad replacement. I forgot the part number. Simple as that. P.S. My 92 300E w/140,000 is coming due soon. Part of the pad is starting to come off, so I'll be right behind you in replacing mine. Good luck!!!

hood pad
 

I did my 560SL about six months ago. Got the complete kit (pad, adhesive, instructions and brush) from **************.com. They claimed that 3M is o.k. but their adhesive was better. I used theirs and found that a couple of weeks later a couple of spots drooped. May have been my fault but, I poked holes and repaired with a squirt or two of Liquid Nails.

I used 3M glue 2 years ago when I replaced mine. It worked fine, but remember to apply the glue on both the pad & hood.

If your pad has a square part that is aluminum on the engine side of the pad, this is for protecting the hood from heat. Aside from this, the hood pad is for noise reduction - not heat protection.

I was changing my spark plug wires 2 weeks ago. And the pad was drooping down so I tore it off. I have probably put on no more than a 100 or so miles afterwards. Is this a huge deal. Or is it just get it fixed when I can, soon?

This is exactly how I did mine and it turned out perfect.
One additional note...I used a paint roller to seat the new pad in place after I got it into position.

I did mine not too long ago. The hood was new, so I didn't have to remove the old pad. I would think that would be the worst part of the job. I just used 3M Trim Adhesive to attach mine. Good luck with yours.

The paint roller is a great idea. Also, letting both sides (pad and hood) get a little bit "tacky" is always a good idea when trying to glue things together. Good Job!!!

3M adhesive
 

The adhesive that you want to use is:

3M Super Trim Adhesive-part #08090. Don't use :

3M General Trim Adhesive-part #08088.

What everbody else said, but adding:

Get the "upgraded" fiber hood pad that was used on later cars, not the spongy foam. And don't just let the adhesive get tacky - read the directions on the can and you'll see that you're supposed to let it set up for at least 10 minutes (IIRC) before putting the pad into the hood. Get another person to help you because once the two touch each other, they're stuck. You can't adjust the fit later, it has to be right the first time. Dry fit it before you spray the adhesive so you get a feel for where the edges have to be.