Strange Hissing Noise

Strange Hissing Noise - '99 A4 1.8T

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Dan Eilerman - 07 Mar 2004 03:36 GMT

I hear a hissing noise when I enter the car; it comes from the rear
passenger side. Lasts a couple of seconds, then goes away.

(I had an accident couple of years back; the rear passenger side quarter
panel was hit pretty bad and was rebuilt. Looks good as new now, but on
close inspection the door lock on the rear passenger door seats slightly
lower into the door than do all the other door locks when they're locked,
not quite as flush with the door as the others.)

Am I just hearing the fuel pump when I get in? Or does Audi use compressed
air to control the door locking mechanisms? I'm wondering if I've got an
air leak that will eventually cost me a bundle when/if it no longer
locks/unlocks my doors.

Any ideas? Or am I just an auto-hypochondriac?

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daytripper - 07 Mar 2004 04:00 GMT

>I hear a hissing noise when I enter the car; it comes from the rear
>passenger side. Lasts a couple of seconds, then goes away.
[quoted text clipped - 11 lines]
>
>Any ideas? Or am I just an auto-hypochondriac?

The central locking system is pneumatic. If you can hear it, you can find
where the sound is coming from, and the pump is located in the right-rear
corner of the boot, in the floor.

/daytripper
'00 s4 6spd

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Dave Smith - 10 Mar 2004 21:16 GMT

dan, daytrip is correct. i have the exact same car and had the unfortunate
experience of some jerk backing into the rear drivers side door. i replaced
the entire door, found one the same color and everything for 350$. when
connecting the harness i had trouble with the connector for the lock. when i
operated the lock i heard a loud hissing sound lasting a few seconds due to
a leak where the connection is, but the lock still worked. i ended up
cutting and splicing the line from my original door. works great now, no
leaks etc.
the air line or hose to the lock is made of a hard orange plastic i doubt
you have a leak in the line, pull the rubber boot out of the pillar to
expose the harness and check the connection. its a plastic connector and is
quite fragile. it may be the source of the leak. good luck.

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Dan Eilerman - 12 Mar 2004 02:17 GMT

Thanks for the tip!

I'm pretty untalented mechanically, so I'll try for an estimate - I happen
to be scheduled for an oil change tomorrow, so I'll ask my dealer about it.

> dan, daytrip is correct. i have the exact same car and had the unfortunate
> experience of some jerk backing into the rear drivers side door. i replaced
[quoted text clipped - 8 lines]
> expose the harness and check the connection. its a plastic connector and is
> quite fragile. it may be the source of the leak. good luck.

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LozW - 12 Aug 2008 11:29 GMT

I have the same. It's a leak in the central locking system. Has anyon
had this and fixed it successfully? The leak on my 96 A4 is in a rea
passenger door. I took the door apart yesterday and the leak is in
plastic box by the lock. I stopped short of trying to remove it as i
seemed a bit involved and I'd like to read someone else's experienc
first. Can't find a guide here - has anyone any experience of repairin
this? I've read that if I ignore it, it will eventually wreck my centra
locking pump

--
Loz

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dave AKA vwdoc1 - 14 Aug 2008 03:42 GMT

Little vacuum solenoid in the lock maybe?
You could plug up that line until you replace/repair the solenoid.
Or take the lock apart to find out what is leaking! ;-)

Signature

later,
(One out of many daves)
1997 Red A4 1.8tq auto

> I have the same. It's a leak in the central locking system. Has anyone
> had this and fixed it successfully? The leak on my 96 A4 is in a rear
[quoted text clipped - 4 lines]
> this? I've read that if I ignore it, it will eventually wreck my central
> locking pump.

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