Under the Dash: It’s done! It’s ugly, but its done.

[Roll]

I finally gathered up a head of steam and tackled the underside of the dashboard.

Pics below show that the front of the dashboard, an area about 12 inches wide and 8 feet long; the part that lays up against the windshield, was completely exposed to the elements under the engine access hood, The long black housing you see is the defroster vent on the passenger side.

I discovered this accidentally a couple of months ago when I had my head inside the engine compartment and happened to look up. I could see the underside of the defroster vents and was surprised to see the only thing between the inside of the coach and the road was a thin layer of fiberglass.

I suspect this is a contributor to the engine noise we get in the coach especially when it revs high to climb hills. The Hushmat may also help keep the cool air or heat inside the coach.

I had already lined the engine cover and much of the surrounding area with Hushmat and it did make a difference but I wasn't satisfied.

So over the last two days I worked at covering the underside of the dashboard with Hushmat. I removed the access door (mainly so I could reach up with one hand and grab a windshield wiper to steady myself) and started on the easier side (passenger) first. It was a difficult job, (for an over 60 year old guy), trying to position the Hushmat up under the dash. Many spots were just out of reach and Hustmat will instantly stick to anything it touches. I had a short roller to press it down but had to use a 2 inch paint roller (sometimes with an extension), to reach some areas. It ain’t pretty but it’s done.

Various pics show inside of dash before, during and after the install. I covered the defroster vents as well all except the nipple for the hose.

Have not driven it yet but tomorrows trip from Ohio to Hilton Head (Down I-75 through the mountains) will tell us if it made a difference or not.

I am so glad to be done with this job.

Gary (and in spite of latex gloves and a long sleeve shirt I am still picking fiberglass out of my skin)

Last pic is a finished pic. You can see the vent is completely covered but for the hose connection.

[B D HOWie]

Very nice job. Looks great to me. It will be interesting to read your follow up report on the noise improvement.


Paul
Big Dog House On Wheels
2013 Coachmen Freelander 28QB
on 2012 Chevrolet 4500
Using FR app

[Roll]

Originally Posted by B D HOWie

Very nice job. Looks great to me. It will be interesting to read your follow up report on the noise improvement.


Paul
Big Dog House On Wheels
2013 Coachmen Freelander 28QB
on 2012 Chevrolet 4500
Using FR app

Took the coach out this afternoon to fill the tank and to get it weighed. It was noticeably quieter although we did not do any significant grades. We are heading out tomorrow and will be traveling South through the Appalachian mountains; that should be an adequate test. I'll post with my impressions.

[redneck 92]

Looks like a great job! Thanks for the update showing your progress on the dash area underside. I am eager to do the same.

[ResQfrog]

Roll,

Please keep us informed on the difference. I was looking at the same idea you had. Just have to find the time.

[Roll]

In HH now. Reduction of engine noise at high rpm is noticeable but not gone. I'm still pleased with the result.

If I had to qualify I would say the combo of lining the engine hatch, sounding areas of the engine compartment and the underside of the dash has made enough difference that had it been like this from the factory, I would not made any changes.

You're not going to keep a V-10 that is only 3 feet away quiet when revving at 4500 to 5000 rpm, but Cindy and I were able to continue a conversation after long grades required downshifts and high revs. Prior to Hushmatt we had to wait for the coach to crest the hill to resume the conversation.

I'm happy now..... On to the next item, outside LEDs.

Gary

PS. 5.6 mpg through the mountains. Guess Hushmatt didn't help there. Lol

[Duckogram]

A veritable masterpiece. In my book, nothing that works is ugly.
Thanks for the thread.

[BLGC]

Roll, did you consider using some type of spray coating? like an undercoating spray. might help and easier to use and not add weight?. not sure if somebody offers spray sound insulation.

[go6car]

Nice job!

[calebgold]

How much / what Hushmatt kit did you get/use?
Amazon has a few different kits. a door kit (10 pieces) and Floor kit (20) pieces and a bigger one with 30 pieces.
The odd thing is the floor kit that is 20 pieces is more than double the door kit 10 pieces. So I would like to get a better idea on what you used. To do both the dog house and the windshield.

It looks great.