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"hoot" sound from engine compartment-- a/c ?

Got a weird one here.

I'm hearing an intermittent "hoot" sound that is higher in pitch than an owl would make. Probably in the ballpark in frequency of the tone that's played with color bars on a TV set/station test pattern (1kHz). If I had to guess, it's probably aroudn 700Hz. It doesn't last long, maybe a second, at most I've heard it for 4 seconds continuously. Crops up once every few minutes at most, seemingly randomly.

I've heard it happened while: stopped and idling, coasting at low speed, starting off and going up a hill and ... here's the one that gets me: even JUST after the car has been turned OFF.

Seems more frequent on hotter days.

Doesn't seem to vary with wheel speed or engine speed.

I've not yet heard it when the Air conditioning is off (but I just tested this on 2 drives yesterday after the idea came to me). The A/C system was serviced about a month ago. So my best guess is the air conditioning system somehow.

What in the A/C system might cause such a noise I wonder? Or how could someone addressing a cooling system leak have screwed up to cause this to happen?

Or could it be something else still? Alas, I could not find an owl in the engine compartment to explain it otherwise.

Reply to
Todd H.
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Does it sound like your security system beeper?

Reply to
1 Lucky Texan

sounds like the AC, have had funny sounds when overfilling the a/c system; id take it back and have them evac and recharge the a/c system

Reply to
StephenH

AC, I just finished fighting the same thing. A little too much gas in the system

Reply to
rss1

I dont' have one, and nah, it's not electronic sounding at all.

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

Cool. That makes sense to me. Thanks for the datapoints! Knowing what it is makes it a lot less annoying.

Think there's any long term system health issue of leaving it as is? I may do that if it stays as infrequent as it is (haven't heard it for a week).

-- Todd H.

2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
Reply to
Todd H.

No big issue with a little too much gas, but the system works cooler with the right amount. Gives room for the gas to expand (cool) in the evap.

Reply to
rss1

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