A/C Woes - Help

The A/C on my '86 Camry had never needed any A/C work, but over the past 3-4 years the cooling has become inadequate. It was still mildly cool but not cold enough. The site glass showed froth. I had a jug of Freon 12 from the old days and decided to add some. While adding gas to the suction side I watched the gauges and my wife watched the site glass.

When I began the suction pressure was 0 and the high side was 100. After a short time the site glass cleared but when I would stop adding gas and let the gauges stabilize were reading 20/150. The book says they should be 28/210 and when both are low it's a sign of undercharge, so I kept adding gas. If either gauge had reached its target value I would have quit, but the gauges never went above 20/150 (except when adding gas). Suddenly, while charging, there was a loud squealing noise that lasted for a few seconds (3-5) -- the compressor stopped pumping, and the button you press for A/C began flashing. After that every time I turn off the A/C and turn it back on the compressor will try to pump for about 1-2 seconds and then quit and the button will start flashing.

Anybody know what has happened and why?

Ken

Reply to
Ken Hall
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Did you weigh the bulk cylinder to watch how much R-12 you put in? A full charge is around 2 to 2.5 pounds, marked on the spec sticker under the hood, most of the time it'll take less than a pound to top off an almost working system.

Did you put a big box fan in front of the radiator for some extra "wind" while testing, and run the engine at fast idle (1500 - 2000 RPM) while watching the gauges? Keep an eye on the evaporator temperature with a chef's thermometer in the outlet duct?

One possibility - you overfilled it, and the compressor is getting liquid slugging in the pistons and stalling, and the safety circuit in the AC Amplifier is tripping like it is supposed to.

When the AC Amplifier compressor sensor doesn't see the compressor rotating for any reason, it drops the clutch as a safety measure and flashes the dashboard light as notification. Otherwise the compressor pulley would lock up and break the fan belt - this could also take out the power steering, water pump or alternator and make the car not drivable. Toyota is smarter than Detroit on this one. ;-)

If it is overfilled, do NOT vent it! Go to a local auto repair and let them recover a little - it's very expensive now, they'll gladly take a half pound for free (that they can resell for $30).

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Bruce L. Bergman, Woodland Hills (Los Angeles) CA - Desktop
Electrician for Westend Electric - CA726700 
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Reply to
Bruce L. Bergman

The pressures were not excessive (assuming your gauges are OK) so perhaps the compressor shutdown due what is refered to as 'non-compressables' ie water, too much oil?

Jason

Jason

Reply to
Jason James

Thanks for your reply.

I d> One possibility - you overfilled it, and the compressor is getting

After I posted my message I blew off a lot of gas. Almost all I think

-- hard to tell. No change in behavior. But, the compressor is definitely rotating for the 2-3 seconds before it all shuts down. I can see the low side dropping. By the end of my blowing off freon, in these 2-3 seconds it would reach into the operating range -- below 30. It seems like there's a ratteling/knocking sound while the compressor is on that didn't used to be there, but then I probably didn't pay much attention to startup sounds.

Ken

Reply to
Ken Hall

Thanks for your reply

With the car is off and two sides have stabilized the gauges read the same. I used that to judge the gauges were OK.

I doubt there's water in the system because it's never been open before and I was careful to bleed all the lines when hooking them up for this charging operation. As for oil, I didn't add any oil, only freon.

Ken

Reply to
Ken Hall

Maybe I should have added, that it was cooling well after the sight glass cleared and before the squealing.

Ken

Reply to
Ken Hall

Not wishing to state the obvious, but the compressor has lunched-out. Mine also produced some cooling, despite the rat-atat-tat noise it was making (bought the car this way).

I think Ken got it when he mentioned overcharging with resultant liquid refridgerant getting into the compressor, damaging it.

It's a salient lesson to all us non-refridgeration mechanics I'm afraid.

Jason

Jason

Reply to
Jason James

Always stop adding once the sight glass is showing clear liquid. I even keep a few tiny bubbles as a safety margin. Pressures will vary depending on the ambient temperature. The sight glass shows you what's going on at the moment. You can always add more on a very hot day, assuming the bubble population in the sight glass has increased.

Reply to
John

Sounds like your compressor is trying/has to lock up. I always add a can of oil between 2 additions of gas. If the gas leaks out, I figure the oil also leaks out, since I see oily dust on the front of the compressor. This might be wrong, but seems to work for me. The bad thing is, if you are in the stages of lock-up, the damage has already been done, and failure may be just around the corner. I would shop Ebay for another one, tons cheaper than rebuilt, and a good time for a 134A conversion. R-12 sells there for around $17-22 a 12 oz can.

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Reply to
Johnboy

My air con is dead but im lucky enough to live where its not a necessity. I'm even tempted to strip it out and save some weight (nigh on 30Kg if im not mistaken) otherwise it would cos me £80 a refil, first time with dye to spot the leak and second with repairs where needed - bit excessive for a bit of chilly air.

J
Reply to
Coyoteboy

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Indeed. If I lived in the UK, I would also not be be so eager to spend money on AC,...but I live in NSW, Australia where in summer car-cabin temps go over 60C and we all get skin-problems later in life thanx to our Celtic skin.

Jason

Reply to
Jason James

Thanks for polluting the atmosphere, asshole!

Reply to
Chris Aseltine

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