Speedco in Brunswick GA (Exit 29 on I95) is my preferred shop for annual generator, engine and chassis service.
No appointment needed and you will receive a coolant analysis at no additional charge.
Engine oil analysis is available on-site for a small fee ($35 or so).
You will be in and out in less than an hour most days.
They may or may not help with the noise issue but they work from a pit underneath the coach and will have a good view if anything is obvious.
Been going there for the past 11 years of ownership of our DP.
1998 American Eagle 40EVS