Welcome Visitor! Please take a few seconds and - Joined
- Dec 26, 2025
- Messages
- 1
- Points
- 1
- City
- Seacoast
- State - Country
- NH - USA
- Vehicle Year
- 2003
- Vehicle
- Ford Ranger
- Drive
- 2WD
- Engine
- 2.3 (4 Cylinder)
- Transmission
- Manual
Hi all,
I have a 2003 2.3L/M5OD with 157k miles. On cold days (typically freezing or below) I get a strange whistling or howling noise from the engine bay. It usually goes away when the engine is under load or warm, but not always. I first noticed this around the same time last year. Since it went away when the engine was warm, I just assumed it was another "old vehicle noise." This year, it has become more consistent, and will sometimes occur while driving or idling with a warm engine. That leads me to believe that it may be something else. However, the sound is just so loud that I can't locate it in the engine bay. I made a recording for reference:
Some notes:
The video doesn't do the volume justice. It's clearly audible inside my house 50 feet away.
It seems to be RPM dependent. It appears to change tone when the RPM changes, and also disappears at some RPM bands before coming back. It almost seems like it changes depending on the movement of the IAC, but I haven't had a chance to chase it down fully. As you can hear in the video, there's a kind of "warble" as the IAC adjusts the idle during the warmup sequence.
If it occurs while driving, it tends to come in quietly, increase in volume, and then disappear. It doesn't seem to come in or out at a consistent RPM/engine load. If I didn't get a noise on startup, then I won't get one while driving.
Everything else seems to be in good, working order. Since I've owned it, I've done basic preventative maintenance in accordance with the manual and replaced some failed components (ignition coil, fuel pump). I checked the power steering fluid; it's pretty dark (likely original) but definitely full. I had planned to change it along with a couple other maintenance tasks this coming spring.
Any help or advice is appreciated. I'd like to fix it just for decency to my neighbors (it's seriously loud), but if it's something benign I'll likely wait until spring before diving in too deep. This is my daily driver and my other vehicle is put away for the winter, so I'd like to avoid breaking something important while freezing out in my driveway.
I have a 2003 2.3L/M5OD with 157k miles. On cold days (typically freezing or below) I get a strange whistling or howling noise from the engine bay. It usually goes away when the engine is under load or warm, but not always. I first noticed this around the same time last year. Since it went away when the engine was warm, I just assumed it was another "old vehicle noise." This year, it has become more consistent, and will sometimes occur while driving or idling with a warm engine. That leads me to believe that it may be something else. However, the sound is just so loud that I can't locate it in the engine bay. I made a recording for reference:
Some notes:
The video doesn't do the volume justice. It's clearly audible inside my house 50 feet away.
It seems to be RPM dependent. It appears to change tone when the RPM changes, and also disappears at some RPM bands before coming back. It almost seems like it changes depending on the movement of the IAC, but I haven't had a chance to chase it down fully. As you can hear in the video, there's a kind of "warble" as the IAC adjusts the idle during the warmup sequence.
If it occurs while driving, it tends to come in quietly, increase in volume, and then disappear. It doesn't seem to come in or out at a consistent RPM/engine load. If I didn't get a noise on startup, then I won't get one while driving.
Everything else seems to be in good, working order. Since I've owned it, I've done basic preventative maintenance in accordance with the manual and replaced some failed components (ignition coil, fuel pump). I checked the power steering fluid; it's pretty dark (likely original) but definitely full. I had planned to change it along with a couple other maintenance tasks this coming spring.
Any help or advice is appreciated. I'd like to fix it just for decency to my neighbors (it's seriously loud), but if it's something benign I'll likely wait until spring before diving in too deep. This is my daily driver and my other vehicle is put away for the winter, so I'd like to avoid breaking something important while freezing out in my driveway.
