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Old 09-05-2022, 04:55 PM   #1
Junior Member
Brand: Thor Motor Coach
Model: 2022 Four Winds 31W
State: Texas
Posts: 24
THOR #27889
Excessive road, engine and exhaust noise in cab

We recently purchased a new 2022 Four Winds 31W. Since day one, excessive road, engine and exhaust noise within the E450 cab has been driving us nuts.

Took a while to figure out the source but it turned out to be coming thru where the E450 cab floor meets the coach floor. From inside, you will see this as a ~2" step-up to the coach floor that runs the full width of the cab. There is a long strip of carpet Thor applied to the face of it and it's capped off with a rubber edge trim. In our coach, this joint was unsealed from below, leaving about a 1/2" open to the outside from side to side.

Solution: Park on a level clean surface, set the parking brake and chock the wheels. With a can of 3M Fire Block Foam in hand (Orange FB-Foam, heat resistant to 240F) and a headlight, crawl under the RV where the cab meets coach. Look up an you will see the junction where the Ford cab floor sheet metal meets the plywood coach deck flooring. Since they overlap, the gap will not be visually apparent but can be felt by touch. It's very difficult to fill with the 3M FB spray foam but can be done by bending the nozzle tube around horizontally and into the gap as you go. Fill the gap from end to end and let the foam setup overnight. Next day, crawl back under with a sharp knife and carefully trim off any excess foam showing. I then used Flex Seal Black Flex Paste, 3lb tub (1lb jar is not enough) and a putty knife to seal over the foamed gap to make it watertight, airtight and yet flexible enough to withstand expected movement.

The drop in cab noise level is astounding from this simple fix. What I don't know is if this a common issue or did Thor perhaps forget to seal this specific joint in our RV when built. So, your mileage may vary.

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Old 09-05-2022, 05:19 PM   #2
Junior Member
Dotsie's Avatar
Brand: Thor Motor Coach
State: Florida
Posts: 8
THOR #27885
Thank you so much for posting this information on the excessive cabin noise. We're on our first trip in a Quantum WS31, and experiencing the same issue. My quick fix is a dog bed placed between the cab seats. Much less noise and a happy dog. Now if we can get the bedroom vanity lights to shut off, we would be set! Thank you for your post and detailed fix.
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air infiltration, cab noise, road noise

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