2.5L engine whine
 

With the ignition issue resolved it is time to discuss a sound my car is making. It is a pretty loud whine from the engine compartment. Related to engine RPM. I'm pretty sure I've checked once without the belt and the sound persisted. AOS has been swapped out since (as it was going bad), but that didn't change this noise. Engine starts and pulls ok, no smoke on start-up or driving. Basically it is just this noise.

As it is difficult to describe I found the same or similar noise on U-tube, but unfortunately without any answer to what it was. So input greatly appreciated;

https://youtu.be/sNW5jA-7hP0?feature=shared

Does it have any CEL or pending codes? Not sure if a standard obd2 reader shows all the codes so maybe try to find an iCarSoft Por or relevant good reader ?

Since you already tested it without the belt, that helps narrow down the possible causes. At first i thought it may be (any) pulley, water pump or anything closely related

No lights. I haven't checked for codes yet as I don't yet have a reader for this car. Guess that a durametric of PIWIS clone might be the way to go.

I'll retest the belt off as it has at least been two years. Confident it didn't change anything, but better to be sure. Will take a few days as I have the alignment scheduled for Tuesday and want to do that first. In the meantime, very open to experience from you all :)

Sounds kind of similar like if you do not have enough power steering fluid in the resevoir.

Confirmed today that the noise persists with the belt off. I made a small recording, but need to see how I can get it available for all.

So power steering ruled out. Also it is engine speed dependent, not gear (also in neutral). Also, this is a different gearbox than before, so not related to clutch / gearbox etc. Something engine.

If all is well, a short video with the engine sound (belt off) is here:
Engine noise on YouTube

That isn't quite the same noise I've had with a loose spark plug, but similar. Check to make sure they are torqued correctly. I have 30 Nm/22 Ft-Lb written for torque, but double check.

I'll have a look for sure. One of the first things I did was to fit new sparkplugs. Too long ago to recall whether it had the sound before. Easy check, so will likely do that this weekend.

In the meantime, open for other options..

Today I had some free hours to try the sparkplugs. One of them wasn't torqued to spec and I could rotate it another half turn before it was correct. Others were ok.

The sound wasn't resolved that way. Still persists, same volume.

Any more thoughts? I tried to listen from underneath the car, but difficult to pinpoint. Sounds more from engine side than exhaust, but couldn't tell a real difference left to right or something like that.

When driving my 98' Boxster with the top up and the radio off I hear a sound too.....but more like a "smooth whirring" when revving. I've noticed for the past 22 years but I have always chalked it up to the mid-engine location (directly behind me) and sound deadening insulation/padding/carpet material.

The car had 31,000 miles on it when I bought it and now has 102,000 (almost) trouble-free miles on it.

I actually very much like the sound I hear....to me it's more of a gentle "whirring" than sounding like there is a problem. I'm sure IF there was an issue sometime in the past 22 years I would have known about it......I just assumed ALL Boxster's made that pleasant sound.....lol

Ah, the classic Boxster symphony! That smooth whirring is practically part of the spec sheet for a mid-engine Porsche. After 22 years and 70,000 trouble-free miles, if it were a problem, you'd definitely know by now. Enjoy the unique mechanical soundtrack—it's part of the car's character

————————————————
Combining power and compactness, the Nema 17 stepper motor is the ideal power solution for 3d printers.

Yes, I guess a whirring sound might be a better description :) So you think this is the usual sound?

I hear the same. Funny part is, it’s smoother than my 997 3.8, which doesn’t make that sound!