[RockCrusher]

Don't hear any squeaking. At the beginning I think I hear a whooshing noise.

All I can offer is my limited experience:

Had a car (Porsche Turbo) in which the engine cover was open, louvered. When I left the car parked in the rain or parked in heavy fog upon cold engine start the accessory drive would make a bit of squeaking -- more like chirping -- noise. Belt slipping. Battery voltage was low at around 12V when it should have been close to 14V. But with just a bit of idling the accessory drive hardware would dry and the noise would go away and battery voltage would become nominal.

None of my cars with a solid hood (or even with functional hood scoops/vents) ever suffered from water on the accessory drive. This includes my MINIs. These got driven in rain upon occasion.

Now it so happens the Turbo did experience -- two different times -- noise from the accessory drive that was not due to moisture. Both times it proved to be a bad idler roller bearing. The first time I heard what sounded like a "dry bearing". Second time there was rather faint and definitely intermittent chirp noise.

With a different car heard a noise -- a faint low rumble sound -- which proved to be coming from the water pump.

I was able to confirm the noise was coming from the accessory drive by removing the serpentine belt and starting the engine and letting it run only long enough to note the noise still present or gone. It was gone. I will mention in this case the belt drove the water pump, power steering pump, A/C compressor. While it was not advisable to run the engine very long with the belt removed with the engine cold a brief period of engine run time with no coolant circulation was not a concern.

However, with at least one car -- my VW Golf TDi -- the water pump was driven by the same belt that drove the camshaft. Obviously removing that belt to confirm a noisy water pump was not something I could do. (Fortunately in 150K miles the water pump was fine.)

Will add that with the noisy water pump I noted the serpentine belt had a sharp (inner) edge. I had the old belt handy and even with 60K miles of service both edges were dull. It was clear the belt was rubbing and this strongly suggested bad bearings which allowed an accessory drive pulley to move out of alignment. Upon checking for bearing play the water pump had some -- but not a lot -- while the other accessory drive bearings were free of any play.

 

[RockCrusher]

Agree with ventmore. Would add, and it is probably stating the obvious, as long as the heating/AC system is otherwise working correctly, then yeah, live with it.

I had a car, a Porsche 996 Turbo, that upon cold start manifested a rapid clicking noise for a moment or two. Had the car in. Tech thought it might be a relay or a ventilation system air door actuator. Rather than fund what could only be an expensive diagnosis of this I decided to live with the noise. Oh the heater/AC system worked fine and if the noise was from a relay there was no other signs of any issues.

And there as also a problem with the engine manifesting misfires when started from cold. Tech offered it might be due to one or more sticking injectors. The engine never misfired at any other time and otherwise ran perfectly. I fixed the misfires at cold start by simply avoiding any real idle time after starting the engine. As soon as possible after cold start I was backing the car out and on the road. Despite the engine still being cold it never manifested any misfires.

But then at some point I noticed the clicking noise was gone and misfires after cold engine start gone too.

What changed? Unfortunately I don't know for sure, but at some point the battery was replaced then the new battery was replaced after 5 months. Then much later the alternator was replaced. Also, I started driving the car more frequently. The Turbo was my "pleasure" car and I was reluctant to use it for my 60 mile a day work commute. But at some point I just decided to kind of alternate between my "daily" driver and my pleasure car.

Later I had another car, this a Dodge Hellcat, that I used infrequently (again it was my pleasure car) and after some time it manifested some issues that long story short proved to be due to lack of use and arising from a low battery that was still able to start the engine with no drama but which resulted in a low voltage glitch at engine start which played havoc with the car's electronics. The solution was to drive the car more often. My daily at the time was my first MINI JCW and it shined as my daily/work commute car. So I considered it a downgrade of sorts to use the Hellcat for my work commute. But the more frequent use eliminated the issues arising from a low battery.

Later with my Scat Pack as my pleasure car it started to manifest issues that I guessed were due to lack of use. I had retired and all my driving was (mostly) pleasure. More usage of the car and the issues disappeared.

Lesson learned. I now make it a point to use both my cars alternating between them although restricting my use of the more "exotic" car for good weather.