You might pull your doghouse and make sure the blanket is still in place underneath. While there check for clearance between sides and or existing sound deadener and engine. You do not want to restrict airflow around the engine while solving your issue. There are several products out there the stereo fans use to control sound on your coach basically you would need to lift the carpet in the front and on the doghouse to install it underneath. Other choice if you can find it is stuff that can be installed outside under the motorhome, again provided you have clearance.
Ray, Cheryl & of course Miss Molly the four-legged child
2006 Dolphin 36' F53 V10 5 speed auto 2 slides 7.5 KW genset