[s-cars] A/C Cycling on/off...

[djdawson2 at aol.com]

Low refrigerant will usually keep the compressor for engaging for anything more than a few seconds.  A system that runs and kicks off is typically suffering from a lack of airflow, resulting in high system pressure cut-off.  This could be the aux fan, a weak fan clutch, a radiator and/or condenser packed full of bugs and debris, or bent fins on either or both the rad and condenser.

If it cuts out routinely, I would be trying to determine if it is the high pressure switch that is turning things off.  Based on what you've said about traffic and heat, it seems to me that this is most likely the case.

Dave



 

 


 

 

-----Original Message-----
From: Andrew B <andrew.sb at gmail.com>
To: djdawson2 at aol.com
Cc: s-car-list at audifans.com
Sent: Wed, Jun 30, 2010 7:45 am
Subject: Re: [s-cars] A/C Cycling on/off...


Well, I checked my Aux fan this morning and it does indeed turn on

with the AC.  I have heard before that low refrigerant could cause the

problem, on QW, but it was more in passing than a "Here's your

answer".  I have heard the afterrun pump turn on before, but not

recently.  I'll keep an ear out for it in the future.



I also checked the codes, and the only thing I really found was a

"Belt slip, Hard, sporadic" that would indicate any compressor issue.

Maybe I'll try and get over to an AC shop for a check and refill...



On Tue, Jun 29, 2010 at 4:28 PM,  <djdawson2 at aol.com> wrote:

> Keeping the CC cluster out of the equation for now.... I would suggest that

> if your A/C is cutting out while in traffic or going slow, that your aux fan

> is probably failing to operate.  This means inadequate airflow, resulting in

> high system pressure, and eventually cut-out due to high pressure.

>

> I would check operation of you aux fan (with A/C on) as a starting point.

>

> Dave

>

>

>

> -----Original Message-----

> From: Andrew B <andrew.sb at gmail.com>

> To: s-car-list at audifans.com

> Sent: Tue, Jun 29, 2010 1:41 pm

> Subject: [s-cars] A/C Cycling on/off...

>

> The other day I was driving my 95.5 S6A from Boston to CT, and shortly

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> into the drive I encountered some heavy traffic.  As I shuffled along,

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> the A/C kept cutting out.  This has happened before, again in heavy

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> traffic, and on a hot day.  Later, after the traffic finally

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> dissipated, the A/C nor Recirc buttons/icons would stay lit, no matter

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> whether I stopped and shut the car off or not.

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> When I got to my destination, I left the car until the next day, when

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> I started it up and the A/C worked fine.  A quick drive that evening

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> with the AC on was fine.  Finally, on the trip back to boston (with no

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> traffic and slightly ~5* cooler temps) the AC worked the whole way

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> home with no incident.

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> Also, late in both drives, my CC cluster became hard to operate.

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> Buttons near the top would not function, but lower ones worked OK.

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> This doesn't seem completely related to the traffic problem, as I

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> could press the snowflake button, but it turned right off.

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> Any ideas?  There didn't appear to be any overheating issues as the

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> idiot light did not come on and the temperature never climbed off the

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> fat line, although is did creep to the hot side of it.  Could my CC

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> head be overheating?  Compressor clutch?  There doesn't seem to be any

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> additional noise although the car does drive somewhat more sluggish

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> with the AC on.

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> Would love to find a solution for this...the one place I want AC the

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> most is where it habitually cuts out...

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> -Andrew

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