Aerodynamic Anomaly?

[TonyPSchaefer]

Priapus seems to have picked up a noise like air being disrupted. It reminds me of when I'm riding in a friend's car with the canoe rack mounted.

I've checked all over and can't find anything out of place. There's nothing to hear until I reach 40 mph. At that speed, it's constant. At 55 mph, it is pulsing. It starts with nothing, increases in noise, then decreases to nothing again. By my count, it's one second increasing, one second decreasing, and one second quiet. But only at 55 mph. I actually have not exceeded 55 mph since hearing it so I can not report on faster speeds.

As I was washing him last weekend, I noticed that the spoiler seemed a little looser than I remember. Nothing overly alarming, but I seemed to be able to wiggle it up and down more than I remember being able to. Not that I try often.

Another item for consideration is that I am due for new tires. I'm still running stock tires after about 47,500 miles.

Thoughts?

[Rokeby]

Did you check up under the chassis?

It's possible that you have a plastic bag or other road debris stuck on
something under there.

Loose mud flap or tire air dam?

[Edit] There are a few plastic belly pan pieces under there too. Perhaps one is
torn and has a flap hanging down into the air stream.

[nerfer]

Rokeby might be onto something. But you might need a helpful friend to hang over the front of your car looking underneath as you increase speed. Above 40 mph your friend should be able to easily spot the problem.

(I am not a helpful friend).

[Sheepdog]

"(I am not a helpful friend)."

LOL! At 40mph who would be?!

[finiyon]

If the sound is coming from the rear and you think that the spoiler may be loose, try some blue painters tape at the base of the spoiler. For a few cents you can eliminate one (of many) possibilities.

[seasalsa]

Tony, you failed to mention if the windows are open or closed! I get the pulsing when I forget to close one of the rear windows.

[Highly ImPriused]

Could it be the cargo area cover? I notice that tends to rattle a bit at times.

[fcc]

Originally Posted by seasalsa

Tony, you failed to mention if the windows are open or closed! I get the pulsing when I forget to close one of the rear windows.

i noticed that the other day and was rather disappointed. pulsing is a kind
word to describe the most annoying sound i ever encountered with a back window
down.

[TonyPSchaefer]

Originally Posted by seasalsa

Tony, you failed to mention if the windows are open or closed! I get the pulsing when I forget to close one of the rear windows.

You are correct, I failed to mention that!

It's been almost a week since I started hear the noise. Of course, I didn't want to start a thread and then find out that it's something simple like the gas lid was open. So as I mentioned, I have spent the week looking, listening, trying to pinpoint what it might be.

Usually when I'm moving at all, the windows are about one inch cracked and when I'm above 50 mph they are all the way up. I have heard it regardless of window position.

It does sound as though it's coming from the back. If I had to pick a side, I'd say back passenger side.

[Sufferin' Prius Envy]

Originally Posted by TonyPSchaefer

It does sound as though it's coming from the back. If I had to pick a side, I'd say back passenger side.

Have you considered an out of round tire? The noise is speed related, and you can sometimes get a pulsating sound from the tires. And if it is a rear tire, you won't necessarily feel it like you would a front tire.