strange noise in dash when turning

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mdb - 27 Jun 2007 21:35 GMT

I have a 97 9000 Aero and have recently noticed a new noise. I'm wondering
if it might be indicative of a low level of freon in the ac system. It
happens when I turn hard, to the right or left, while the car is moving.
There is a squeaking, whooshing sound. Almost like liquid shifting from one
side to another. I suspected the cabin temp sensor so removed that last
weekend and cleaned it. As a further test, I stuck a small shaft into the
cabin temp sensor to stop that fan. Still got the noise when turning the
car. Less noticeable on gentler turns. No strange sounds at all when driving
straight ahead or hard stopping.

Any ideas what I might be hearing.

Thanks.

Michael

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Steve B. - 27 Jun 2007 23:12 GMT

>I have a 97 9000 Aero and have recently noticed a new noise. I'm wondering
>if it might be indicative of a low level of freon in the ac system. It
[quoted text clipped - 11 lines]
>
>Michael

The refrigerant in the a/c system won't make noise when you turn
corners. It is a gas under pressure and doesn't really move around
because of turning forces.

You might be close to the culprit though.. Sometimes the condensate
drain for the a/c system clogs up and the plenum starts to fill with
water. I had an old Cadi that would dump about a gallon of ice water
on your feet during a turn when it clogged. After a couple of times
of this happening I learned to keep that drain clear!

I don't know exactly where the drain is on your hose but it should be
coming out the passenger side firewall area.

Steve B.

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bozo - 28 Jun 2007 03:49 GMT

It is likely a plugged evaporator housing drain - the trapped water sloshes
on turns and can 'bother' the fan - which makes the noise and can eventually
over-stress the fan, too. A good site is quasimotors saab 9000 site - in
the faq section, there's a part about the ac evap drain with a pic of the
drain outlet (of course it is under the car) - site is: quasimotors.com -
go to the faq section and then the ac evap drain section and click on the
pic link to see the outlet

ALSO - you don't need to stick anything in the opening of the cabin temp
sensor to see if it is running (could be costly for you to do that) - just
take a smallish section of single ply toilet or kleenex type tissue and rest
it against the cabin sensor grille - the fan sucks in so if it is working,
it will hold the tissue in place. Over time, the little temp sensor bulb in
there can acquire a "helmet" of crud and that can affect sensor accuracy -
that can be resolved with a spritz of compressed air from a photo/computer
type air-blast cleaner can

Rick

>>I have a 97 9000 Aero and have recently noticed a new noise. I'm wondering
>>if it might be indicative of a low level of freon in the ac system. It
[quoted text clipped - 28 lines]
>
> Steve B.

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mdb - 28 Jun 2007 17:40 GMT

Thanks for the suggestion about the evaporator drain. I'll check it out.
As for the temp sensor, I knew it was working but wasn't sure if the bearing
in that unit might be the source of the noise. I stopped the little fan and
did a few hard turns to see if the noise stopped. It didn't. I assume the
drain problem will continue to worsen until it's unblocked so will get to
that asap.

> It is likely a plugged evaporator housing drain - the trapped water
> sloshes on turns and can 'bother' the fan - which makes the noise and can
[quoted text clipped - 49 lines]
>>
>> Steve B.

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th - 30 Jun 2007 19:17 GMT

> ALSO - you don't need to stick anything in the opening of the cabin temp
> sensor to see if it is running (could be costly for you to do that) - just
[quoted text clipped - 4 lines]
> that can be resolved with a spritz of compressed air from a photo/computer
> type air-blast cleaner can

You can also listen for the fan just after turning the engine off. The
fan runs for several seconds with no engine running and that sound is
clearly audible.

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still me - 01 Jul 2007 16:56 GMT

>You can also listen for the fan just after turning the engine off. The
>fan runs for several seconds with no engine running and that sound is
>clearly audible.

Yeah... don't fool with the mechanism. Unplug it if you want, but
treat it nice, they are expensive. FYI - A new one will not make much
noise, even with the car off. When they get older they get noisier
(even after cleaning, go figure).

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