Hey Scotty. I'm Scotty too.LOL .Im a long time fan and value your channel.I rescently had to to over pay and buy a used truck and if I were to pay payments It was to be something descent.I drove around second hand cars for to long that were old.But now I have something very nice and Im tring to take care of it .Ihave an issue with a loud rpm sensitive growl only when putting on diffroster or heat thing.its loud and tells me something is wrong.I turn it off it goes away.I turn it on and something in the front of the engine iside starts whining and is rmp senitive. Do you have any clue what the hell that is?Thank you Sir I could really use a break.Its a beautiful KingRanch and my daily driver
Sounds like the blower squirrel cage has gotten lopsided or broken.
i saw a couple vids about the heater plastick armatures breaking off and getting taken for a ride.Thats probly about right .I just cant figure out why it sounds like its under the hood and on the left bank of engine some where
sounds like a failing AC compressor clutch
If you get a long steel bar and put it to your ear and start listening to the idler pulley, turbo, alternator, ac compressor and any other rotating assembly, your should be able to hear anything out of the ordinary, especially since you said it was RPM sensitive. Let us know what you find out. Could be something as simple as a bad belt, too.