A/C Question 200q 20v

[TooManyAudis at aol.com]

Well, it's hot down here in South Carolina.  Damn hot.

Took my 200q on a trip to Wilmington yesterday (160 miles each way), and 
everything went well until around 1:30 pm.  A/C was blowing around 45-degrees, 
which kept the car plenty cool.  Mostly highway driving to that point.  Early in 
the morning the low-pressure switch kicked off the compressor a couple of 
times, but it settled in and ran consistently after 5 or 10 minutes.

After 1:30, there were some problems.  First, the outside temp was about 95.  
Second, I was doing more driving in the city.  A/C compressor started 
shutting off due to the high pressure switch kicking in (been monitoring channel 17 
on the Climate Control diagnostics).

Couldn't cool below 60 or, at times, 70 from the vents, leaving hot and 
stinky.  

After doing a bit of research on the archives, I have developed a two-part 
theory as to the cause:  

1)  slightly low on refrigerant (system converted over to 134-A with a new 
receiver/drier earlier this year).  This I can solve relatively easily.  I have 
all the hoses and connections, as well as a robinair pump, so I started with a 
good dry system to work with.

2)  High pressure switch controllling the 2nd speed on the fan probably not 
working.   Once I got off the highway, there wasn't enough airflow to keep the 
condensor condensing and the pressure shot up in the system, activating the 
high pressure switch controlling the compressor.

Any other thoughts?  Car drove very, very well besides the A/C problem, and 
it is certainly something I would like to address ASAP.

Couple of other points:  There is a slight leak of oil around the compressor 
manifold, and I did not clean or replace the orifice tube when I converted.  
It cooled fine from the start, so I don't think the orifice tube is blocked, 
although I have to visual inspection to confirm.

I'd be happy to get this system through the summer by adding a few ounces of 
134-A every 4 or 5 weeks, but I'd rather not tackle replacing the Compressor 
or changing the manifold seals until temps cool down in the fall.

Please let me know your thoughts.

Thanks,

Tom