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Discussion Starter #1
What's the buzz that I hear from the front driver's side of my s40 after I turn it off? It sounds like it's just behind the headlight. It's pretty loud and sometimes it can last for up to a minute or so after I'm parked and gone. I can even hear it over the engine noise when I'm out of the car with the engine running (like tonight when I hit the mailbox on the way down the driveway).

I've never heard that with any car I've owned in the past. I feel like it's trying to create some kind of pressure, but I'm just not sure. It's been driving me crazy even since I bought it. Any ideas? Thanks, folks!
 

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If it can make you feel any better it is driving me crazy too but well it's there and has its purpose :(

It's the vacuum pump. the little silver round pod here:


I believe it is used to make sure you have a proper air vacuum under certain situations and to assist brakes in neutral.
 

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Discussion Starter #3
Yes! That's it. I made the mistake of touching it a month ago - that bad boy was HOT! Quite a humbling moment... ;)

The dealer replaced my 'brake vacuum pump' at my last service interval - threw a CEL a couple of days before regular service came around. You think that's the same part?

Does everyone's last so long after turning the car off? My girlfriend constantly tells me my car is still making noise as I'm walking away from her (the car, not the girlfriend). That magnifies the 'driving me crazy' feeling. :D
 

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Yes! That's it. I made the mistake of touching it a month ago - that bad boy was HOT! Quite a humbling moment... ;)

The dealer replaced my 'brake vacuum pump' at my last service interval - threw a CEL a couple of days before regular service came around. You think that's the same part?

Does everyone's last so long after turning the car off? My girlfriend constantly tells me my car is still making noise as I'm walking away from her (the car, not the girlfriend). That magnifies the 'driving me crazy' feeling. :D
Lol, just tell her it's the turbo stil spinning its awesomeness :)
 

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Sounds like you have a leak. It will run like that sometimes, but it should not do so continuously, and definitely not to the point to being hot to the touch.
 

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Just like to add something to this, I never heard this buzzing after shutting off my S40 T5. Though when I shut it down it does make a Vacuum sound but this last maybe 2-3 seconds after shutting the car off.
 

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i get that sometimes
does anyone else get a whine that comes at start up? in around the passenger side headlight and the passenger side wheel well?
sorry if i thread jack
 

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I get the whine at start up like something is winding up. drrrrrrrr LOL
 

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Discussion Starter #11
Quick follow up on this one:

I went to the dealer for service today. I noticed my AC wasn't blowing cold a couple of days ago and they found that there was a freon leak at the service port. They tightened it down, recharged the freon (or whatever more earth-friendly refrigerant they use) and I was good to go. BUT - I asked them to take a look (or rather listen) to my constantly running vacuum pump.

The culprit was a 'faulty brake vacuum check valve'. They replaced it and, voila, the buzzing stopped. Poor little brake booster probably almost wore itself out again. I anticipate a short life out of the pump and just hope it fails before the warranty expires. The service form lists my replacement part as part number 31201433-5 with the description of 'vacuum hose'. I recently did a thorough wipe down of my engine compartment, so I can't tell what looks new! :) I looked it up and it looks like one of the hoses between the booster and the pump. Wish I could tell which one it was - must have been a tiny crack.

Thanks again for all the help - you guys were spot on with the diagnosis.
 

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Oh ; the Cost to get it done ?

Let Me add 2 cents , so Engine Designers have gone to Great Lengths to rid this - and Designed the pump to run off an Internal Drive - which makes it much easier on the Ears , but
I don't think it will make it
vary easy to change or service . ;)
 

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Part number 31201433 is the check valve (with small length of hose attached) that connects at the brake booster. It keeps the booster unit properly "charged" even as the amount of vacuum in the line fluctuates.
 
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