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

[Thomas R Green]

Scott Mockery has a good write-up in his diagnostics section for
trouble codes and clearing.  Until you clear them you will be seeing
the same stored codes.  Make sure you record these codes for any
repair shop that is checking the a/c.

http://www.sjmautotechnik.com/

You don't mention how long this belt has been in service, but it should
not look worn or shiny as if it is glazed from slipping.  You can  
observe
the belt with the engine running and a/c on to see if things operate
smoothly or the belt and tensioner jerk a lot and perhaps hear any
noises in the compressor or clutch.  If you have a belt problem, you  
need
to fix it so you can find out what is happening with the compressor.  Is
the clutch slipping or the compressor locking up.

The channel 51 temp is Celsius.  You can spray a small stream through
the radiator and condenser backwards to flush that debris out you see
while the engine is running and the water should transfer the heat much
better;  maybe enough to keep the a/c on.

You can check the a/c pressures with a gage set.  Most FLAPS have
them for free use but they are usually not well kept and you don't know
what residue is is them, particularly oil.  Harbor Freight sell a set  
for $30
that are adequate for any DIY work.  You will have some knowledge of
what is going on with the system, but not a complete diagnosis, and
what are you going to do then?  If you are doing the repair yourself, it
is a good investment.  If not, the repair shop can tell you the  
pressures
as well as the repairs needed.

The quattroworld thread you referenced is mine.  If you click on my
name in the QW post you will find my email.

Tom

On Jun 30, 2010, at 6:21 PM, Andrew B wrote:

> Well, I checked the belt and it looks worn, but not cracked.  My
> receipt from the shop where I had work done includes a serp belt on
> the list (and I was charged for it) so I assume it was done (part of a
> complete head replacement).  It is tight without much play.
>
> I checked the codes again today, same sporadic blocks, same sporadic
> hard slip, and the 223 high pressure switch sporadic.  The new one was
> 22.5, high pressure 120x open.  The radiators do look clean and
> healthy, with no holes or bent fins or dents.  Some debris, but not
> much.  Nothing on the 52C graphics channel indicated anything.
>
> Also, when I checked the engine temp channel 51C, it read 5o.  The
> engine was not warm, but is that supposed to be in C or F or is
> something screwy there?
>
> -Andrew