Weird chirp/whistle

[NickFerrell]

This morning, a new noise started, and I DO NOT like new noises.
While accelerating, there is a high-pitched chirp/whistle noise that is intermittent.
Sometimes it's there, sometimes it isn't. Sometimes it suddenly stops and suddenly comes back.
I examined the engine and fluids, and everything seems to be 100%.
It was initially happening whether driving or parked, now it seems to only happen under load.

...help? Any guesses?

[So Cal Mark]

loose exhaust?

[baltobernie]

Check the guibo?

[urbom]

squirrel in engine compartment?

[RRoller123]

My AFM flap was slightly dragging, and did this exact thing. Took me nearly a year to figure it out. It sounds like crickets as you are driving along. Sanding the housing gently and slightly and slowly took care of it.

[porkchopious]

This morning, a new noise started, and I DO NOT like new noises.
While accelerating, there is a high-pitched chirp/whistle noise that is intermittent.
Sometimes it's there, sometimes it isn't. Sometimes it suddenly stops and suddenly comes back.
I examined the engine and fluids, and everything seems to be 100%.
It was initially happening whether driving or parked, now it seems to only happen under load.

...help? Any guesses?

It could be the carb gasket. If it has a leak, the air being sucked in through a tiny crack can cause a whistling noise. If you can replicate the noise with the hood up while revving the engine you can confirm the problem by spraying carb cleaner or WD-40 around the carb base. If the noise goes away by the fluid being sucked in and thus temporarily blocking the hole, you then have your answer. The solution would then be to replace the carb gasket.

Good luck!

[DanD]

I would start with the fan belt. See if you can spin the alternator pulley with your hand, by grabbing the fins and pushing on them while the car isn't running. Old, glazed belts can squeal when driving or parked.