Tips for insulating motorhomes, in particular the Mercedes 508 and 608

Acoustic Insulation for a Mercedes 508 and 608

Mercedes 508 and 608 insulation

The Old Timer vans of Mercedes are one of the most popular vehicles, which, in some cases, are literally being transformed into fantastic motorhomes. This type of Mercedes van is ideal to convert into a motorhome, but from an acoustic point of view this situation is less ideal. In this article we focus on the 508 and 608 type. Besides, we will describe how to solve the most common sound problems. Most of the insulation methods can also be applied to the Hanomag and Hanomag-Henschel.

The outside bonnet

The most common sound problem is noise produced by the engine. The van contains a small bonnet made from steel at the outside, under the front window, and a bonnet in the cabin, the well-known bump. As for insulating, it is very important to apply the right products at the right place, so make sure to attentively read this article. The bonnet from steel at the outside has to be treated first. You can do this by using so-called anti-drumming mats like STP Black Silver or Vibraflex Normal. These products prevent the bonnet from resonating, avoiding a ‘gong-effect’. The material also adds mass to the bonnet, reducing the amount of noise it radiates. On top of the anti-drumming mats you then apply absorption material in order to absorb the engine noise. In the case of the outside bonnet, where you have enough space between the hot engine parts and the absorption material, we advise you to use Acusticab with a minimal thickness of 19mm. This product is self-adhesive and provided with an oil- and moisture-tight top layer.

The inside bonnet (bump)

Anti-drumming can’t be applied to the inside bonnet, at least not at the side of the engine, because of high temperatures. It is possible to equip the outside of this bonnet with Vibraflex Extreme anti-drumming mats. In order to finish the whole thing and in order to add another layer of insulation, you can apply Isomat VM on top of the Vibraflex. Isomat VM (floor mat) is not self-adhesive, but can be attached using Zettex glue spray. At the inside, the bump can be equipped with Merfocell GW. This is a self-adhesive absorption material with a top layer of glass cloth which can bear temperatures of about 100 degrees Celsius. In case of even higher temperatures we recommend using Aluglass, a product which is also used as a heat shield. For both products the same principle applies: the thicker, the better.

Bottom plate, bulkhead and wheel arches

Through these surfaces, engine and driving noise can enter the vehicle. Ideally, they are insulated using Vibraflex Extrem or STP Aero Bomb. Equip as many surfaces with these products in order to achieve an optimal result. Preheat the products in order for them to be flexible and completely cover the substrate, especially when its surface isn’t even like with wheel arches.

Doors, side panels and roof

Often these are large surfaces that quickly resonate, and thus radiate noise. Equip minimally 70% of these surfaces with anti-drumming mats (ones that are not too heavy). As for the side panels and doors, we recommend using Vibraflex Normal. STP Standartplast products can be used for all surfaces, also against the roof. These anti-drumming mats are less heavy and easy to mount, which saves you time.

Thermal insulation

Thermally insulating your motorhome or van is possible with Akotherm polyester wool. Fill empty spaces from, for example, the dashboard with this material in order to achieve optimal insulation results. We recommend using a minimal thickness of 40mm for behind the interior panels.

More information about insulating vehicle

On our tips page Sound Insulation for Motorhomes you will find more information. On our vehicle page you will find several applications including instruction videos.

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