[Scotty97]

My 07 SC has been making this noise for a little while now and I can't figure out what's causing it. The sound definitely gets louder/higher pitched the faster I run the engine. Because of the overall cabin noise I can't tell if it's louder when going fast on a highway.

It's a whirring or more phonetically "ArRRoooOooo"

It reminds me of a sound old manual TM Ford trucks used to make, not that that helps you any.

She's got 155k on her, in the last 18 months: new AC system, new serpentine, new starter, new water pump. New tires and brakes next week. I didn't notice the noise particularly soon after any of those repairs(most were done by a shop, the more basic stuff I did myself).

Any tips much appreciated folks!

 

[fleetw00d]

Some no cost troubleshooting. Let it idle. Does the noise change while turning the steering wheel back and forth (changing load on the power steering pump)? Does the noise change any (get louder maybe) when turning on electrical accessories (lights, including high beams, rear defogger are the quietest electrical load so you can still hear the noise)? Turn on the AC, it the noise stops, then it could be in the clutch mechanism (which locks up when AC is on). If you've got a stethoscope, listen to those components and the tensioner pulley.

 

[Scotty97]

Some no cost troubleshooting. Let it idle. Does the noise change while turning the steering wheel back and forth (changing load on the power steering pump)? Does the noise change any (get louder maybe) when turning on electrical accessories (lights, including high beams, rear defogger are the quietest electrical load so you can still hear the noise)? Turn on the AC, it the noise stops, then it could be in the clutch mechanism (which locks up when AC is on). If you've got a stethoscope, listen to those components and the tensioner pulley.

All excellent ideas, I'll give em a try. Thank you for the time and response!

 

[Scotty97]

Well, it's definitely coming from the power steering pump. The very slow loss of fluid I've noticed helps paint the picture. I really appreciate the tip! Looks like swapping out the pump is within my wheelhouse as well. This group always comes through for me!

 

[fleetw00d]

I've only pulled one at a salvage yard where most of the front end had already been removed. Gonna rebuilt it so I have a spare waiting if I need it.