J-Rat

iTrader: (2)

Every year about this time, the topic of AC comes up (big suprise there). So in a possibly vain attempt to stop the horde of AC threads, or maybe to give you all something to refer to, I am gonna hit up a brief list of possible problems/solutions.. PLEASE FEEL FREE TO ADD TO IT!!!!


My AC compressor doesnt turn on (clutch wont engage):

Okay this could be a number of things. Main points, either your fuse is blown or your pressure is too low (or to high!!). Checking the fuse is a no brainer, and you can also check for 12 V at the positive wire attached to the AC compressor. Got 12 V? Then I would suspect low or high pressure. The BEST way to test for this is to get a pressure tester from your local auto parts store, and check the pressure on your low pressure line. Should be a Schraeder valve covered by a black cap (large tube on the firewall). This reading MUST be taken with the system on. Once you get this reading, you can figure out what may have happened. (IIRC running pressures are around 30-45 PSI on the low side)

MY compressor turns on (clutch engages):

This is most likely your AC compressor malfunctioning. Especially if your pressures are correct.

My compressor wont turn, and eats belts:

Compressor is seized.


Can I recharge it myself?

Yes, you can aquire R12, just like any other licensed AC technician, if you want. All you need is to take the ASE Refigerant Recovery Quiz located here: http://www.ase.com/Content/Navigatio...nline_Quiz.htm

What is Freeze 12?

This is a drop in replacement for R12, that costs signifigantly less then R12, and uses the same oils. Still requires a licence to purchase. Runs at comparable pressures to R12 and cools every bit as good. As always its reccommended to evacuate the system and add only freeze 12 and its oils (although addmittedly, I have mixed themwith little problem). http://www.freeze12.com/

What about R134a?

Its been my experience that retrofitting to R134a is not beneficial to our 16 or so year old systems. MANY people here have blown up coolant lines (including myself). R134a runs at a much higher pressure, and seems to cause lots of problems with our systems. Also, the system has to be evacuated and the proper oils have to be reinstalled (as well as new O-rings).

How can I find leaks?

Lots of the refrigerants can be purchased with either a colored dye (RED) or a UV dye that shows up under a black light. This will help you locate and correct leaks when installed in your system.

Okay, the disclaimer:

I wrote this very quickly, so I may have missed some key points. I freely invite anyone to add thier experience/expertise to this thread. Also, I AM NOT RESPONSIBLE FOR WHAT HAPPENS TO YOU!! Your AC system runs at high pressures and uses VERY HAZARDOUS CHEMICALS... Use caution!!

J-Rat

iTrader: (2)

I will add more on how to actually charge your system when I am not so tired...

evileagle

iTrader: (1)

Maybe you could point the rest of us to a good write-up on A/C removal

totallimmortal

I Scrapped my broken AC last month, i'm sure i'm gonna hate my self for it in the summer but it never worked anyway and I doubt i ever would have fixed it. Looks like I'dd need a sunroof installed for a little more air flow, found a place near me with a great reputation 330 sound resonable for a manual glass sunroof installed?

Maxthe7man

R-134a pressures are not much higher, in most systems the 134a will run at virtually the same pressures as the 12, the problem with r-134a is that its molecularly smaller than r-12, thus you need impermeable hoses with a liner with 134a..
Also in high temp applications , its been found r-134a oil return is ok with older oils on short line runs, however its been found that polyolester and cfc's don't like each other, and tends to form acids and sludges...Max

RotaryResurrection

iTrader: (8)

The best way to find leaks, without wasting time or money, is to take the car to an a/c service center and have the system pulled under vacuum. This tests for leaks everywhere without wasting any freon.

Markus

Better make this a sticky before 100 more questions start to pop-up everywhere...

good info by the way.

asherwood

Is this Freeze 12 anything like Glacier Gold?

I answered my own question with a little surfing, NO

Maybe I should have done some more research before buying a case of GG. Unfortunatly I don't hink that Freeze 12 is available into Canada. I don't know if I can bring it back while on a road trip to the US?


Decisions, decisions!

derek1987

j-rat, how do you get certified for freeze 12 or is it the same ASE Test you have said above.

Thank you
Derek

J-Rat

iTrader: (2)

Its the same test

Here is the pressure table for R12 and R134A:

http://www.delanet.com/~pparish/pt-table.htm

3RotorRocket

Just take that **** out...who needs air condition when your windows are down with the top open cruisin along at 60mph+

J-Rat

iTrader: (2)

Better rethink your statement..

SBi_Owner

I usually test for leaks with a charge of nitrogen and a small ammout of 12. This keeps you legal for charge and release as per EPA 609 cert. You can then use the sniffer, bubbles or UV leak testing oils.

As far as MVAC cert 609, you can test online for cert, I'll give the website if anyone is interested.

Adam

SBi_Owner

I usually test for leaks with a charge of nitrogen and a small ammout of 12. This keeps you legal for charge and release as per EPA 609 cert. You can then use the sniffer, bubbles or UV leak testing oils.

As far as MVAC cert 609, you can test online for cert, I'll give the website if anyone is interested.

Adam

J-Rat

iTrader: (2)

Bump

Falcoms

also, R134a is corrosive to aluminum lines (hey, go figure, to save weight, the compressor and lines are aluminum in the FC...weird)

nopistons

You can buy Freeze 12 from sherco-auto.com. They didn't ask me for a license when I purchased a Freeze 12 kit from them. 3 cans, the can-tap and hose, and new fittings, shipped, for under $50. (They're in Florida.)

DaleClark

iTrader: (55)

Hands down, the most common problem with FC air conditioning is leaks. Freon leaks out, low pressure switch kicks the compressor from turning over, no AC.

I've been in cars with a proper 134a conversion, and it does blow *cool* but not cold. Our system just isn't sized properly to work right with 134a.

The drop-ins like Freeze 12 or Hotshot do work really well. But, it comes back to the problem of trying to find the leak. I haven't really sorted out where the most common FC leaks are - my guess is the O-rings at the various fittings in the lines. The heat from the engine eventually bakes them and starts a leak.

I have also seen improperly installed cone intakes rub against the high pressure line and tear a hole, as well as improperly routed cruise control or throttle cables rub against the low pressure line on the firewall.

The O-rings are CHEAP from Mazda - I got a whole set for a few dollars at the local dealer.

Of course, after opening the system to install the O-rings, you need to pull it down to a vacuum with a vacuum pump then charge the system. Then you have to hope that you found the leak, otherwise another expensive batch of freon goes out into the air .

Anyhow, fixing AC is really not that hard, but it can take some head scratching. There's not many special tools you need either - most expensive is the vacuum pump, and many times you can just rent those.

Dale

J-Rat

iTrader: (2)

Thanks Dale, my point exactly!

SBi_Owner

Actually, you need to pressureise the system to find leaks and use a sniffer or bubbles. If you draw it into a vaccume and there is still a leak, you will be drawing air into the system which can destroy the system. You only need to draw the system into a vaccume AFTER you have fixed all the leaks to remove all the air and liquid from the system. The water in the system will evaporate at a low temp under 15in Hg. Like I said before, use nitrogen and a small amount of 12 to find leaks.

Adam

Maxthe7man

I think you better retract yours, I am air conditioning and refrigeration mechanic by trade with 12 years exp.. I do this for a living everyday, you don't...
The only real difference between cfc and Hcfc systems is the hoses and the drier materials.. 99.9% of the r-134a compressors on the market today are r-12 compressors charged with POE instead of mineral, most of the compressors we have foudn that were pieces of **** on r-134a, were also pieces of **** on R-12...Max

J-Rat

iTrader: (2)

Did you read the quote?

Here, let me help you:



Now R12 and R134a have interesting qualites.. One runs higher pressures when colder, then the other takes over when warmer... I even posted the pressure tables earlier in this thread... But no matter, I am not going to get into a flame war over it. I maintain that R134a is bad for our systems, and I have personal experience to prove it. You say it doesnt. Thats fine. Thats what this thread is for...

Maxthe7man

If you had any experience with it, you would know that statement is largely false... I converted an air dryer today, it ran 125 psi on r-12 and 125 psi on 134a...You can cut and paste all the BS you want...
max

J-Rat

iTrader: (2)

Okay,

According to the pressure table (unless its wrong), the difference in pressure for R12 and R134a at 170 degrees F, is about 40 PSIG. With R134 being the higher pressure.

Now lets think... What temps do you think are underhood in the middle of a Tucson summer and the AC is going? Its going to be FAR higher then 170 degrees... At approximately 70 degrees Farenheit, R134 running pressures start raising at an exponentially higher rate then R12 .

Maxthe7man

The real problem with it, is it leaks easier, the POE oil that is generally used with it , loves to absorb moisture, which causes copperplateing on the discharge valves, acid formation , forzen off txv's and accurators..etc etc, alot of people try and run old dessicants that are logged with moisture with poe and 134a, thats like doing an oil change, and only changing half the oil, and using the old filter...
Nothing wrong with the gas, just the what people do with it...Max