This insulation is quite important.  Not only does it reduce noise, but it does protect the paint.   My old 230E crazing in the paint above the hot engine from driving a few years with no insulation.   The car wasn’t even that old back then.   The paint on this car is nice and original and I don’t want to damage it.

I used the same method I used back 5 years ago on my W126 300SE.   To start with, I used a plastic scraper to remove as much of the old one as I could.

I found for the bigger lumps, it was easier to have the bonnet in the regular position.   Once I got most of it off, I then moved the bonnet into the service position and moved the sheet up.   This is the longest part of the job.  It doesn’t matter if all the old glue doesn’t come off, but its important there are not any loose bits.

Once I had the old one cleaned up, It was time to apply the adhesive.  As with last time, I used Seallys Kwik Grip Vertical Gel.  It has the right temperature rating and is still holding the insulation on my 560SEC and my old 300SE perfectly, five years later.

I find its easiest to apply it with my fingers using 7mm gloves.   The W123 requires a little more than a can and a half.  I took the opportunity to change gloves when I opened the second can.  It seems to eat into the gloves if you don’t.

The Seallys product suggests waiting 20-40 minutes before mating the two surfaces.  I prefer to do it sooner, as it gives me a bit more ability to move things if I don’t get it quite right first go.   For example, in this case, I didn’t have it aligned properly against the leading edge of the bonnet, so I was able to peel it back and re-apply.

I also use gloves to apply the W123 under bonnet insulation.   That way, if I get a bit of glue on my fingers, I change gloves and I don’t spread the glue around.   I think I must have used 5-6 pairs of gloves to get the job done.   When I got a bit of glue on the paint, the can suggested white spirit to remove it.   I didn’t have that, but hand sanitizer worked great.

As with earlier, I find it easier to start with the bonnet in the regular position.  Once the pad is generally in the right place, move to the service position to work on the lower edge.

Once that was done, I lowered it again to tuck in the leading edge.   The whole job takes 1-2 hours depending on how long is needed to remove the old insulation mat.   I find this job pretty easy to do myself, but that maybe because I am tall and can reach most of the bonnet.

Doing the job at the same time as the 450SLC resulted in three cans of the Seallys adhesive across both cars.    While I was there, I also replaced the two clips for the sun visors so they were not flopping around.   They are still available new from Mercedes-Benz.  They are the W126 part number that supports a light in the mirror.   Not as cheap as they used to be, but still available in the colour I needed.

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For the 560SEC, I had a genuine Mercedes part.    The coupe is different to the sedan.   For the 300SE, I have one made by Febi.   Unlike the genuine pad I put on the 560SEC, the Febi pad is smooth.   The fit was very good – it did not need any trimming.

The procedure is the same as before – first step is to scrape off the remains of the old one.    There was a lot more debris on the 300SE.   You could also see where somebody had tried to use some sealant on the edges to try and glue it back up in vain.

As with the 560SEC, I used an old bed sheet (the same one) to catch the debris.   I also used a plastic tool to scrape the old one so as not to gouge hole in the paint.    It is not essential to get every last trace of the old pad off.   if it is not coming off with a plastic scraper, the glue will stick to it just fine.

The bedsheet also makes collecting the debris into a rubbish bin rather easy.   A queen size sheet means the whole engine bay is covered.  Three months later, the 560 pad is still holding well.  Based on that, I used the same Seallys Kwik Grip Vertical Gel.   This product is rated to 130C.   If the temperature near the insulation gets above that, the engine is well and truly cooked and the insulation is the least of my concern.   It spreads on easily with a 7mm nitrite glove and being the gel doesn’t drip down when being applied.

The gel product does look a lot like I have applied butter to a rather large piece of toast.   As with the 560, I used 1.5 800g cans   The leftover half can from May was a little runnier than the new can, so I used it on the pad rather than the bonnet.

While applying the pad, I found it easier to put the bonnet in the normal position.   When fully vertical, I could not reach the top very well.  Once finished, I put the bonnet vertical as I figured it would dry better that way.   I will be using the E350 for the next couple of days to allow it properly dry.    This job should protect the paint and reduce the noise on the 300SE.   As with the 560, I was able to do this on my own with relative ease.

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