Nozzle Replacement: Squeaking Noise?

I had my old, worn-out nozzles replaced with new ones today!

The car runs more smoothly, produces less exhaust, and, most importantly, doesn't smell bad anymore!

For that, it now squeaks very quietly emotionally with the injection of diesel!

I removed the sound insulation, but besides a harsh running noise, I can't hear anything else! I'm currently attributing that harsh running noise to the new injectors! So, it's normal. Also, the injector listening test using a stethoscope (with a 30cm screwdriver) doesn't reveal any squealing from the injection system!

The squeaking sound is most noticeable near the left wheel arch when the car is idling.

It squeaks under load, but not during acceleration.

Is the load on the V-ribbed belt always the same? Regardless of whether it's under load or thrust operation?

I'm asking because my serpentine belt is making a strange flapping noise! I hope that's the reason for the slight squeaking!

Do you have any ideas about where the squeaking sound might be coming from? Maybe it's a defect in the nozzles!

Of course, the workshop foreman didn't hear anything!

AFN, 235,000 km!

Okay, here's the translation:

Thank you.

Manuel.