1990 New Yorker A/C Question

My NewYorker recently needed an Air Conditioning (R-12) refrigerant
charge, I can't tell you how hard it was to find a shop that still had
some left, but I did finally costing me ($114) just to "top it off".
The A/c system is now as cold as can be. It had been very slowly
leaking out over a period of about 6 years. A conversion to R134a
would have cost me $230+, so I thought this was a bargain. The A/C
specialist at the shop told me that it took "2 ounces under a pound"
to fill it up and "the high pressure side is a bit high, when you get
home, take a hose and spray down the condenser". I haven't done this
yet, but a physical examination of the condensor revealed no leaves or
road debris on it, its clean just as it was made at the factory.
Hmmmm. Can anyone shed some light on this? Something else also I
noticed is that the compressor has now started to cycle on and off
frequently, usually its shortly after you first turn it on. Sometimes
it still cycles after that, sometimes it stays on. Very strange. It
never did this before. Could it be low on refrigerant oil?
Comments?Btw, the sight glass on the filter/drier is now clear ( no
bubbles or foam as it was before)

 

Be careful about these conversions. Seems like everyone I talk to that
converts their R-12 system to an R-134a system is unhappy with the
performance and results. Basically an R-12 system was specifically
designed for R-12 and the same goes for the R-134a system. I still
remain partial to R-12 A/C's 'cause I have had great luck with them but
I have also seen some R-134a's that can perform as well as R-12.

I believe he is telling you to spray off the condenser so it cools it
down, thus dropping the pressure on the high side of the system. This
keeps the A/C system from developing leaks as a result of extremely high
pressure.

Hope this helps!

 

Sounds like the tech might have overcharged the system.

 

R-134 is inherently less efficient than R-12 as a refrigerant. R-134
systems that work well are "bigger" to account for the lower efficiency.

If R-134 was better than R-12, we would have all been switched to it
years ago. |>)))


Dan

 

It is.

Could be an overcharge but more likely this is unimportant. Refrigerant
pressures in auto A/C systems are only good at specific temperatures
of the condensor and air coming out of the ducts in the car, and even
then it's some hit and miss. Some manuals have charts some don't.

What is the outside air temp and what is the air temp in the vehicle?

If the outside air temp is 100 degrees and the inside of the car is 120 and
you just turned on the A/C and the car is idling, I would expect the clutch
to stay engaged.

But if the outside air temp is 65 degrees and your idling at 1500 rpm I
would expect cycling.

This is how it's supposed to be when filled.

Ted

 

I'am beginning to suspect it could be an overcharge, hmmm, the tech
seemed to know what he was doing though. Perhaps the equipment he used
was outdated, he told me he hasn't sold any R-12 in more than a year.
When he told me he had put in half a pound and "there is still a few
bubbles left" and then he put in 6 more ounces, he was looking at a
guage on this 4 foot tall machine when he said "thats it". And then he
told me the hi pressure side was a little high and I should spray it
with a hose. I hope an overcharge won't hurt the system, ~ could the
high presssure switch be kicking off the compressor?

Outside temp was about 83 degrees F. Inside temp was about 75 to 80F
cooling down.

That seems logical

Something else thats been bothering me, when R-12 leaks out of an air
conditioning system, does the oil charge (lubricant) leak with it?
Should I put a 3.5 ounce R-12 lubricant charge into my A/C system?
Will it help?

 

No, he didn't. Not if he released your car with improper pressures and
told you hosing-down the condenser would fix it.

Please. There's no such thing as "outdated" manifold gauges and charging
scales.

Watching bubbles in the sight glass is NOT the correct way to determine
the system's state of charge.

An overcharge puts more stress on every component of the system.

Exactly what is almost certainly happening.

DS