jcantera

Hey gang,
I have been following some threads on A/C trouble and determined that I needed to recharge my A/C. I bought the gauge kit and refrigerant and followed the book and everyone's advise here. No one addressed what to do when the compressor cycles off. Let me explain...

While the engine was on, A/C to max re-circ air, speed 4, I hooked up the gauge to the low pressure service port and began recharging. My wife (in the car) noticed an immidiate difference... yay! As the gauge hit the optimum range for charge, the compressor shut off, and the pressure wnet through the roof to over 70 psi. I called a local buddy of mine and he said to ignore the reading if the compressor is not running. When the compressor kicked back on, the pressure stayed high, so I bled off some of the pressure until I was back in the normal range. Now, when the compressor kicks off, the pressure still goes way up, but when it kicks back on again, it is normal...

Should I be concerned? Or, should I follow my friend's advise and ignore the reading when the compressor cycles off?

Cheers!

nycgps

iTrader: (1)

Nope. You did it wrong

first off, why did u have to recharge it ? Was it because its not cooling? compressor not kicking in ?

ken-x8

The reading only counts when the compressor is on. You're measuring the low side pressure...which is low only when the compressor is sucking that side.

Ken

ken-x8

You missed the part where he said the compressor was running. And the part where his wife said it was better after charging, which suggests it was not cooling.

Ken

ASH8

Not having "touched base" with car air cons..lately..

Unless things have changed, (I doubt it), you have to first make sure all your fittings/joints are home or secure...

Then you must Vacuate (suck out) all the bad air with an electric vacuum pump.

Then Add refrigerant, check for leaks (special tool) and top off.

That is normally it.

I am personally not a fan of Adding Refrigerant ONLY Via "running" the Cars Compressor.

Frankly, for the cost I don't know why you don't take your car to an air con specialist.

Do it once, do it right..

nycgps

iTrader: (1)

the compressor will ALWAYS work (unless the clutch /electrical parts are completely dead) when you charge, even if it has a huge leak somewhere else in the system, it will work, at least for a while.

R134a wont "disappeared" for no reason. So he might have a leak somewhere. it could be the condenser, it could be the o-rings, etc.

jcantera

Thanks for the assist guys. I think ASH8 says it best... if I have any more issues, it goes to the pro's.

Cheers!

ASH8

^^^ Agree..

A dye based air conditioning leakdown test uses a colored dye to find freon leaks in your air conditioning system. Using this test, a colored dye is injected into the a/c system which will be visible under UV (ultra-violet) light at the point of a leak anywhere in the system. The test is performed under full pressure with the air conditioning system closed (sealed as if you were driving under normal conditions).

Cruder methods are the use of Soapy Water sprayed on joints etc for Bubbles (leaks) at Seals or Joints..

nycgps

iTrader: (1)

I would say this method probably works the best. but sometimes there are areas thats very hard to detect.

I fixed my own FC's A/C this way,

It has a leak, I used 2 bottles of R134a with Green Dye, but after 2 bottles, I checked almost everywhere and still couldn't see it, then after I left it there for about a day or 2, The leak showed up, its at the bottom of the Condenser corner, you can't even see it with flash light(or the UV light that comes with the package), u have to take 1/2 the stuff apart to see the leak, those dye dries up too fast before it had a chance to drip to the floor.

Now my FC has colder A/C than my 8, that is just sad.

(Off topice : I use R134a just to find leaks, pure R134a sucks, Good for leak checks, thats about it. Im looking for ways to get rid of R134a and PAG oil and use other stuff + Ester oil in my 8)

I will probably never be able to find the leak this way. if its a really slow leak maybe. but it takes too much time.

ken-x8

Of course there's a leak. R12 didn't disappear without a leak, either. But if it's losing charge slowly, and pressure is still positive with what's left, then just topping it off is OK. That's why you can buy cans of refrigerant. After all, R134a is safe for the environment, so you're not doing any harm.

The compressor won't run if the charge is too low - there's usually a low pressure switch to protect the compressor from running dry.

If it leaks out faster than a can every couple of years, then professional attention is usually needed. Although my experience with leaky home AC systems is that techs prefer to come out every year and recharge rather than try to find the leak.

Ken

ekliptik

iTrader: (3)

i have fixed a/c systems in alot of cars. everything from replacing parts to just adding some refrigerant.

my question is does anyone know what the low side high side pressure readings are supposed to be on the rx8?

my rx8's a/c cycles on and off too frequently which is leading me to believe it is just low on charge.

RotaryTherapy

iTrader: (1)

Check the low side and high side valves, the things with the grey caps marked H and L on it, my L cap actually unscrewed the valve stem inside which caused very slowly leak of the system.

EDZRIDE

iTrader: (1)

Try this: http://foxed.ca/rx7manual/2003mazdarx8/

ekliptik

iTrader: (3)

^ awesome dude! that will be sooo much help in the future with everything!