Ford V10 High Speed Whistle
At the risk of this sounding like a "Click and Clack-The Tappit Brothers" episode, I have these engine observations which don't immediately make sense.
-2020 Tiffin Open Road; 43,000 miles;
-happens with and without toad attached
At speeds above 48-50 mph and RPM's in 2250 range, the engine is (relatively) quiet when even slightly accelerating, but if I take the foot off the pedal, a whistling sound can be heard (>5000 Hz is my estimate).
The whistling sound increases as the speed increases. I do not run over 65 mph.
The sound is not present at high speeds and higher RPM's, likely because engine braking may be occurring(?).
The sound is not present while in PARK and revving then idling.
First noticed sound approximately at 40,000 miles
So far, quick check underneath chassis finds nothing loose (like a shroud or heat shield or ??).
And as far as a fan belt, I cannot even determine a visual location to spot check. I know it's there but I haven't put my coveralls on and really crawled around.
Any 'puzzlers' out there have any thoughts?