robertbartsch

I did a cam swap recently. I bought a vacuume pump and guages to refill the system. Although not certified in anything but accounting (CPA) I did do lots of A/C work in the 70's before they knew R12 was a bad-***-gas.... back then, EVERYONE used to discharge the freon into the air...

Anyway, my R13 AC blows cold about 98% of the time. During really hot days, however, the system shuts down after about 45 minutes on the highway. If I turn the AC off for a few minutes, and then turn it back on the AC blows cold again....

Is this some computer problem; I don't think it is related to a physical problem with the system - it appears to be some electrical circuit that is telling the compressor to not engage the AC clutch?

Is my system overcharged; i heard somewere that the R13 systems don't like too much gas...?

Any thoughts?

PS - We need a new category topic - "Air conditioning"

Tom@SpeedInc

iTrader: (5)

CFC-12 or R12 isn't bad gas, it does it job rather well, it just contains ozone depleating CFCs.

As for your situation, did you use the vacuum pump after you reinstalled the condenser? To me it sounds like your accumulator is full of water and is freezing up when you are crusing. I have had GM cars (malibu and cutlass's lately that have had bad AC control heads, the AC light flashs and turns off after about 5mins.) I think you have a blockage though. Check for frost on any AC lines.

overcharged? what are the gauge readings?

robertbartsch

OK; one other question; the vacume pump was used after re-installation of the condensor - i put in two cans of freon and a small can of oil....

What is an "AC control head" - where can I buy an accumulator/dryer for the car. I would rather not go to a GM dealer since they rape you over the coals for this stuff... they wanted to charge me 80 bucks for a new ignition key recently!!!

Tom@SpeedInc

iTrader: (5)

ok two cans of refigerant assuming 16oz so 2lbs, if your lucky to suck it all out. And a can of oil, how much is a can of oil. Sometimes I recover no oil on a recharge. And if so the case I just put in a pump of dye (has easter oil in it) and call it a day.

What kind of oil was it? most GM/ Harrison compressors take PAG 150.

The AC control head is where you press the buttons in the dash.

You could get a accumulator from car quest but any GM parts dept. will have a accumulator and it will be under $100. Probley under $50. Even though you evacuated the system with a vacuum pump were you able to pull 29.4" of vacuum? Water boils at 68* at 28.5" of vacuum and at 6* 29.4" vacuum, this is all dependant on no leaks in the system and good functioning vacuum pump that has it pump oil changed frequently.

Anytime you open the system you should replace the accumulator or reciver dryer, alot of times if you just going to replace an O ring you can get away with not having to do so. A half hour or so on a humid day with lines off that desicant (accumulator) is soaked.

So bottom line robert, take your car to an HVAC professional to have your problem inspected and repaired. Then if they wanna replace the accumulator and the problem is control head, its their problem. But that won't happen cause they are professional and do work like this everyday.

P Mack

iTrader: (6)

Who would you consider to be an hvac professional? I need to get my system refilled. Would you trust the guys at one of those firestone service center places?

Tom@SpeedInc

iTrader: (5)

Their are shops that specialize in AC repair down your way, they do the job right. Dealership guys (like myself) do a good job and have more expirience with common problems that save you money by repairing it right the first time.


Firestone....... I'd say they are dartboardish, some guys take pride in what they do and others should be forbidden from holding a wrench.

Certain independant shops will do a good repair and not try to cut corners.

robertbartsch

Yeh ok that is good advice - but I was an AC tech in decades past, I have a new vacume pump, guages and I like to do all the work on my cars... It is not a cost thing, it is at this point in life - a hobie thing for me....

I like GM replacement parts becasue I know they are OEM, however, every time I go to my dealer I have to order the parts and I get really soaked on the price (example - 85 bucks for a plastic alarm key chain door opener, 175 bucks for head bolts, and on and on and on...

Anyway, I'l take my chances with the Car Quest guys and I'll replace the accumulator/dryer and pump down the system for a couple of hours then recharge....

Bye-the-way, is it unethical to discharge the new gas into the upper ozone?

Tom@SpeedInc

iTrader: (5)

Unethical, well its a greenhouse gas and can incur a $25,000 fine if the EPA finds out. And a good way to let in moisture. Have you determined that the accumulator is the problem rob? Car Quest is good aftermarket parts so is NAPA, you take your chances when you work with autozone or pep boys.

robertbartsch

i did not think the new freon was a greenhouse gas....if this is the case, why does the government allow sales of the new freon to non-licenced folks who buy it at Martha's Place?

is there a cheap and easy way to recover the gas?

thanks about the Napa , car quest info....

robertbartsch

I bought a Delco acccumulator drier from a parts store for $65...

Question: Does the vacuum pump also remove moister from the AC system?

jimmyblue

iTrader: (11)

You'd have to have the gauges on there, and see
if your low side and high side pressure switches
are cutting you off or the pressure is proper. For
example, if you have evap icing you may be stuck
with all your Freon sitting there liquid because you
can't get enough airflow to boil it back to the low
side. More Freon won't really help you (or if you
do get enough in there to overcome this, you may
be slugging the compressor with liquid). If you
see fog coming out the vents right before it quits
then this is a good possibility - then check
drainage, might have to clean the evap core of
cat hair, dunno if there is a filter on our models'
evap box inlet or not, etc.

Tom@SpeedInc

iTrader: (5)

The primary purpose of a vacuum pump is to remove moisture, water boils in a vacuum. 29.4" of vacuum water boils at 6* so at room temp you can remove much moisture as possible. Though once the driers desicant bag is soaked with water it won't let it out.

Any moron and joe can buy refrigerant in 16oz cans, how they use it is whats regulated. Have to be 609 certified to purchase refrigerant in 30lbs quantities.