Reinsulating the Engine Bay and Firewall

This is the firewall.

It's a sheet of metal and it's the only thing that separates you from the engine bay. Normally, the firewall in a car is insulated and then covered with carpet or rubber mats to reduce road noise and heat from the engine.

Our firewall had really old , ineffective, cracked rubber on it, and we described the removal process in a previous page. However, we couldn't just leave it bare because that makes the driver's area extremely loud and the heat from the engine is unbearable on your legs. We did a lot of research on insulations that can withstand high heat and reduce road noise. However, materials that are good at sound reduction are not always the best at heat insulation. So we compromised and used a combination of products: 30sq ft of thermal insulation from GuteAuto (really light material but great at insulating heat) and 36sq ft of sound deadening insulation from Siless (really heavy sound damping material).

Step 1: Clean.

The insulations we chose are self-adhesive, and while the adhesive is really strong, it really does not like dirt, grime, prior adhesives, etc. So, with the proper personal protective equipment, we used denatured alcohol to scrub the area super clean.

Step 2: Measure/cut your insulation to fit.

Because the thermal insulation is flexible, it can easily ben around angles or bumps or edges. It is more manageable if you're using multiple smaller sheets because that way you can peel back a small section of the paper backing at a time and make sure you're applying it correctly before removing more of the backing. If you remove the entire backside, now you have an unwieldy sticky insulation that is VERY reluctant to let go of your bus.

Step 3: Roll with it

I used a drywall roller because that's the closest thing to an insulation roller I could find at Tinkermill, but it got the job done. Using firm pressure, roll over the insulation pad to get out any air bubbles. If your pad is fancy, the raise bumps will flatten to let you know that you've rolled it properly. Ours did not do that, but I rolled hard enough and long enough that I'm convinced I did it right.

Step 4: Repeat until your arms fall off

Until your bus begins to look like she's afraid the aliens can read her thoughts and the aluminum foil hat is the only thing protecting her.

I mean... Until you've covered enough surface area to really make a difference or you run out of insulation and need to unroll the other 15sq ft you bought.

After using all the heat insulation and seeing the difference it has made for our experience driving in the bus, we're really happy with the heat reduction. We are going to add a layer of sound insulation to the inside of the firewall, but pictures of that process will come soon. That part of the project is still in progress.

Insulating the Engine Bay

The hood insulation that came with the bus was also old and cracked and probably not doing the best job anymore. In fact, every time we popped the hood open, a little bit more insulation fluff would fall off. We replaced it using the same process as the firewall, but only used the heat insulation. This part was more difficult because parts of the hood were hard to reach and roll properly.

Our friend Alison dropped by to help out with this process and with roof painting, which was great because she is amazing company, she is highly flexible, and she has impossibly long limbs to help reach all the more difficult places. Alison also has some pretty sick dance moves!

Having replaced the old hood insulation, we've noticed that the hood is not getting as hot after running the bus as it used to. We would call that a success!

Sound insulation!

When the Siless sound insulation finally arrived, it became super clear why sound insulation is good at dampening noise. It's heavy and dense. For comparison, 30sq. ft. of heat insulation weighed 1.25 pounds, and 36sq. ft. of sound dampening insulation weighs in at a whopping 16.45 pounds!

This stuff was way stickier than the sound insulation, and it destroyed about a pair and a half of latex gloves for every piece cut and applied.

We applied the sound dampening insulation on top of every spot of the firewall where the heat insulation was applied to give Brie a double layer of insulation. We also applied some around the driver's seat hardware and inside the driver's door - which had zero insulation in it to begin with. That explains all the rattling coming from the door!

We has some extra, so we added it to the ceiling right above the driver and passenger seat. Then we added some to the walls right below the first windows.

Carpet and Cargo mat

Time to cover up the silver pads with something a little more.... car-like. Car carpet and a cargo mat to protect our floors.

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