Every since my car was worked on after my accident last year, I've had issues with my AC. I had the opti and misc. parts changed. The AC was disconnected at the shop, and when it was reconnected, I've had problems ever since. There has been one leak already, and was fixed. This time I want to fix it myself.

How hard is it to track down a leak? Can I buy the dye that's put into the system?

 

If the ac system was left open for a long time you will probably continue to have problems. It is best to evacuate the system, see if it holds a vacuum (leak test). Then flush it with a flush kit and compressed Nitrogen, change the reciever/drier or accumalator and the expansion valve or orifice tube. Then recharge with freon and the recommended amount of the proper type of refrigerant oil. Other than replacing the entire system this is your best option and while not 100% it has a good chance of getting it working reliably again.

 

Frankly I'd just take it to an a/c shop and let them use an electronic sniffer to check for leaks (Poop Boys often advertises this as part of a $29.95 a/c tuneup). Should take all of 15 minutes and maybe 50 Bucks (some will do it for free). I like the sniffer because it can see where you can't - like inside the Evaporator Case and if it's leaking there (and GM's often do), a dye won't do you any good. Once you know what the situation is, you can map out a plan to fix it yourself or repost what they find out here. If you do go to a Shop, they will probably also check your operating pressures. Note what they are, the outside air temp and post that info too.

 

A good A/C technician will add dye when the system is charged especially if you tell the shop you have a recurring leak. A special light is necessary to let the dye show up when the refrigerant leaks out.

Unless you have the proper tools, equipment and knowledge, it's best to let a professional handle A/C system diagnosis and repairs.

 

 

Here's a big'ol long bunch of info on doing this yourself.

Number ONE is to study up and take the EPA Certification Test and get a license to do this type stuff (refrigerant handling).
And, you'll know how to handle/ise refrigerant in a way that will protect the air quality and the environment.
Anybody that wants to learn how to do their own AC work and has the intelligence to learn should START with getting the certification. It's not that difficult and you'll learn a LOT.

I have several dye injector tools.
I don't like the dye method. If you have a catatrosphic leak maybe they would be ok. But if the leak is THAT big you don't need the dye.
You will need a GOOD infrared light source and poke around in the dark to locate a leak with dye. The bulbs in my infrared lights are the size of a standard home 100/150 watt flood/spot lights.
Usually the dye sprays everywhere. Also a lot of oil/tranny fluid/power steering fluid will light up under the infrared making finding the leak you're looking for difficult.

Got a couple of electronic 'heated diode' leak detectors with little suction fans in them.
The electronic detectors ARE good for checking in the evaporator box.
They are a little tricky to use if there are any fans running in the shop while you are 'sniffing' around with'em. Any air currents can confuse them/you as to where the leak actually is.

Don't laugh, this works.
My favorite method is soap suds in a bottle spray.
Check just like you're looking for a leak in a tire.
Spray around all the hose connectors, service ports,etc.

BTW, you DO have the caps on the service ports WITH good seals in the caps don't you?
The shraeder valves are notorious for leaking so keep'em capped up.

The compressor seal may be leaking... .

Look for oil around ALL the connections and around the front of the compressor seal.

Get any old spray bottle and fill it up with liguid soap suds and water.
Use it to try and 'sniff out' any leaks you may have.

Read This:

The 'vacumm down' and see if it holds vacumn method is ok for checking a system you EXPECT to have no leaks. Do this before recharging with freon to make sure you aren't going to (1) Waste Freon, (2) Vent freon into the atmosphere.
It is totally useless for FINDING a leak in a system that you KNOW has a leak/leaks.
If you KNOW the freon has leaked out you don't need to remove the freon and vacumm it down first. You already KNOW it won't hold vacumn.
There is No need to depressurize the system first thing. Use whatever pressure is still in there to help you find the leak point/poiunts.


Good old soapy water is the cheapest and sometimes the easiest way to probe for leaks on an existing leaky system.

TIP: Go back over what has already been 'fixed' on it VERY carefully.
A large percentage of the time the 'problem' is faulty workmanship/materials used on the last repair. NEVER rule out what 'someone' else has done as a cause of the problem as it is, in most cases, the actual trouble.

Order up a box full of assorted o-rings compatible with your refrigerant.
I 'think' you may have an R-12 system on your '93 unless someone has converted it to R-134a.
The 'green' and 'blue' o-rings are probably the ones you'll want to get.

BTW, it's almost impossible (at least for me) to get the correct refrigerant charge into the system during the winter using the low pressure reading as the reference point.
Wait until it's a nice WARM day (70~80*) to recharge the system.
Or, wait until spring/summer.
If you DO have a leak, it will leak less during the colder winter months (TEMP/PRESSURE Chart).
But if the AC is not working you'll lose mix of dryer air for your windshield defroster until it's repaired.

Another BTW, you may need to jump the low pressure switch to get the compressor going if the system is severely low on refrigerant.

Third BTW....
IF you have R-12 in your system you are going to want to be REALLY, REALLY careful about venting ANY and ALL R-12 into the atmosphere.
That's because (1) IT's Against EPA Regs. !!!! (2) It's Expensive.
(3) I'll get sunburned more easily (4) You will be ruining the Polar Bears home.(5) The paint on all our Vettes will fade more quickly when they are in the sun.(6) Ther will be more skin cancers/melanomas (sp)
(7) JUST DON"T DO IT

You WILL NOT want to charge the system up until you are 100% SURE there are no leaks where that R-12 Gold can sneak outta there.

Fourth BTW...
You can pump up a flat system with more inexpensive R-22 just to look for leaks. Don't use much, just enough to get pressure in the system so you can find where the leaks are.

Gather up this stuff and you'll be well on your way to doing your own AC work:

(1) Gauge Set with quick disconnects for the refrigerant you're using.
(2) Freon Recovery Unit (DO NOT VENT FREON)
(3) Vacumm Pump (most recovery machines have one built in)
(4) Assorted refrigerant hoses to plumb everything up
(5) Soap Bottle
(6) O-Ring Set
(7) Oil Injector (In case there was a BIG leak, etc.)
(8) Can Tap (if you want to recharge out of a can)

Stuff you can get later:
(1) Refrigerant Scales
(2) Additional Adapters for different manufactures fittings.
(3) Assortment of Injectors for oil/dye
There's a lot of things you'll want if you really get into this.

Good luck with your project.



Heckkkk darn, that's almost a book.

 

You pretty much covered it all. Sounds like instructors copy at the union hall, AT.
A halide also works good for R-12 & 22.
Never use that dye. Even if it shows a leak when you turn on the light, that crap will be all over the place often masking the actual point of the leak. For the home mechanic soap bubbles is about the best.
If you want to save yourself alot of frustration let a pro do it. Don't you know anyone in the HVAC/R Trade?
As far as venting.... what's a little dyminemous venting. You don't want to add to the hole in the ozone layer.......Hmmm, Let's see....If refrigerant in a vapor is heavier than air......condenced(liquid) it's heavier than water.......I wonder how it gets up there?
Be careful jumpering the low pressure sw. If it low enough to trip the low pressure sw, most likely it will end up running in a vacuum. With a leak that's not good. Have your guages on and hit it with refrigerant. Near impossible to detect a leak on a system in a vacuum.
Hey jim, all good info but you didn't happen to mention that the items to gather up, if you don't have them, will easily cost a couple grand
I think what Jim is trying to say is.... leave it to a pro.