Wanted: A/c Self Repair Recommendations

OK, it's summer and I've decided to get my 96' Sonoma's a/c working again.

There are several re-charge kits available through the parts stores, so does anyone have any preferences on which are the most complete and effective?

I picked-up this vehicle about 2 1/2 years ago ( in November 06') and never tried to use the a/c until the following summer. It didn't blow cold and I really didn't care too much as I don't normally like to use a/c.

But, things change.......

Any suggestions/recommendations on a do-it-yourself fix?

TIA

try getting some R134 with the dye in it to see if you have any leaks coming from any lines, just be careful, that dye could stain your driveway or your clothes. We had to jump my compressor to come on since mine was so flat out of Freon, so make sure when you turn your compressor on, it kick its on...

There's the industry standard hose attachement thingies for the cans and there's some propriatary ones. I'd go for the standard which screws onto the can, then you pierce the middle with a screw in valve thing.

HF sells R134 guages. The auto parts stores sell UV dye sets with a little UV penlight and some goggles that help. Add a half a can of 134 so that the compressor will kick in (low pressure switch), add a squirt of dye, get the system circulating, check for leaks, fix leaks, recharge.

I am in the same boat. I think information on finding leaks is easier to find than information on fixing leaks. Every article says find the leak and repair. How do I repair? What is involved in replacing all the O rings? Does every fitting have O rings, or just some of them? Are there products you can apply to a leaking component from the outside as opposed the leak fixers in a can which have not been working for me?

Depending on the connection or where the leak is, fixing leaks is going to be different. Usually a connection is leaking, but not always. Sometimes just tightening it up will fix it. Most of the time, not. Pull it apart, take the O ring to the store, get a new O ring and hope that fixes it. Some hoses don't use O rings. The ones on the 220D I had were like that. Sometimes the hose or tube is broken/cracked and you have to replace it. The 2' long aluminum tube on the front of my Truck was a bill from the Toyota dealer, and no other options were available. One end was cracked, and the connectors are oddball. Sometimes the Shrader valve is leaking. Get a new AC specific one. Finding the leak is usually a lot harder than fixing them.

Finding a/c leaks is a remarkably difficult job. Oh sure, I can find a ruptured hose. That's easy. But that pesky leak that loses a can's worth of freon a year, I can never find them. Not with my sniffer, my black light leak detector, etc.

The intertec Walmart recharge kits work fine. They are what I use for a/c R-134 changouts. They work fine with the oils from the R-12 systems. The most important part of the job is the vacuum drawdown. Do that part well and the conversion is painless.

If you're just regularly topping off an existing R-134, the kit with the gauge built into the charger handle is fun to look at.

I have never had an A/C leak. Either it works great, or it is a total failure of a major component. Hopefully you will have better luck.

Here is a quick and easy $25 test.

Head to autoparts store for a can of r134 and a re-usable hose. Be sure to get the type that has a re-usable hose. The cans with the hose built in are crap. Expected cost $25.

Examples:
http://www.acehardwaresuperstore.com/quest-r134a-high-mileage-refrigerant-stop-leak-p-69209.html?ref=42
http://www.acehardwaresuperstore.com/r134a-recharge-hose-with-gauge-handle-p-89868.html

Under hood, follow the AC lines and find the valve that the hose connects to. There will be two valves but they are different sizes and the hose only connects to one. These valves look very much like a valve stem on a tire.

Follow directions on the can but it is just like adding a can of fix-a-flat to a tire.

Write down the date on the calendar and see how long your AC continues to work. My Volvo has a small leak and this method is good for about 4 months. At $10 per can (using re-usable hose) this is good for me with one can getting me through the hot months.

In reply to jrw1621:

I opted for the $25 parts store re-charge kit, with the re-usable hose and pressure gauge included. It included an 18oz can, plus I purchased an extra 13oz can.

The compressor is kicking-in, but unfortunately there is still no cold air.

Ugh, there are more things to check-out....

It gets complicated at that point. You need some guages (HF). You can do some diagnostics with you hand on the hoses at various points. Where's it cold? Where's it not cold? I'm gonna guess at this point that the compressor is likely shot, but you need to hook it up to guages to see. It may be time for a professional diagnosis.

Did you pull a vacuum on the system first?

In reply to GTwannaB:

I was in the same boat but I found a guy on Ebay selling a auto A/c guide for 5.00 bucks. It walked me through the process of findinding the leak and charging the A/C. It was easier then I thought...

In reply to iwanna1974:

I just looked up in my guide that you can use a spray bottle with a mixture of dish soap and water and spray it liberally over the hoses and fittings and if you have sufficient pressure in the system you should see bubbles forming where the leaks are. My system would leak down in a couple of days but since I fixed it so far still cold..... Yeh

oldsaw wrote: The compressor is kicking-in, but unfortunately there is still no cold air.

Very generically, but a leaky system stops cooling when it's down roughly 1 can.

Really leaky ones that have lost almost everything take two cans to get them up high enough to start cooling again.

Get an R134 manifold set. They're like $69 from Harbor freight and they'll pay for themselves a thousand times over in the future by letting you top off/recharge your own AC. If you're feeling spunky and want to do the job right, grab a vacuum pump while you're there. 3 cfm should do the trick.

Stop by an A/C shop and have them reclaim what's left of your R134. Take it home, install the manifold, open only the low side (blue) valve. Hook the yellow line to the vacuum pump and let it suck for about 15-30 minutes. Shut the low side valve and turn off the pump. Note the vacuum reading on the gauge and let it sit for at least 5 minutes; more is better, and recheck the gauge. If it hasn't lost any vacuum you should be OK, but you're not home-free yet. Loosen the fittings on the lines to close the schrader valves, pull off the hose fittings, and check that the schrader valves aren't leaking. If they are, Auto Zone has a fix kit that includes two valves, two caps, and the little tool to install them.

Always charge a vacuumed system. You can't have air in there with the freon. Hook up the manifold, do the vacuum for 15-30 minutes, then hook a can of R134 to the yellow hose. Start the car with A/C on max (recirculate), full fan. Slowly open the low side valve. The low gauge will nearly peg. Watch the high side. When it reaches about 100 psi, the compressor should kick on and cycle a few times. I charge from a 30# cylinder, but you'll have to stop a couple times and change cans.

At this point, take the RPMs up to about 1500 and hold them there. Continue charging until the low side reads between 30-40 and the high side reads 250-300. Those are very generic numbers. For instance if you set up using those numbers in the winter, come summer time your high side would spike at 500 and blow a hose or damage the compressor. Once you get in that ballpark, go ahead and rev it up to 3000 or so and watch the high side. If it keeps climbing fast even though the RPMs are steady, or if it goes over 400 psi, you probably have overcharged it. Just bleed a little off while no one is looking. :) If you notice that you can't get these numbers, something is wrong. For instance, if the compressor is kicking on and the low side is spiking while the high side isn't, most likely you have a restriction in the dryer, or the compressor is failing. A spike on the high side could mean that the condenser or the expansion valve is clogged.

When you're done, close all valves and unscrew the tops of the hose fittings (this will make sense when you get the manifold). Now gently unscrew the fitting on the freon can and let the freon escape from the yellow hose. The exiting freon will cause frostbite so don't let your hands linger there. Then you can take the yellow hose off the can. Now, open the high and low side valves to let the pressure escape from those hoses before you pull them off the AC lines.

Some generalizations: 1-never add freon to the high side by opening the red valve

2-never add freon to a system that hasn't been vacuumed

3-topping off is an OK thing to do which lets you skip the vacuum part, but it indicates that there is a leak and it might accelerate the leak.

4-never vent R134 into the atmosphere. That's the legal thing to say. Most shops will let small amounts vent without feeling guilty.

Enjoy icy cold air.

curtis73 wrote: Get an R134 manifold set. They're like $69 from Harbor freight and they'll pay for themselves a thousand times over in the future by letting you top off/recharge your own AC. If you're feeling spunky and want to do the job right, grab a vacuum pump while you're there. 3 cfm should do the trick. Stop by an A/C shop and have them reclaim what's left of your R134. Take it home, install the manifold, open only the low side (blue) valve. Hook the yellow line to the vacuum pump and let it suck for about 15-30 minutes. Shut the low side valve and turn off the pump. Note the vacuum reading on the gauge and let it sit for at least 5 minutes; more is better, and recheck the gauge. If it hasn't lost any vacuum you should be OK, but you're not home-free yet. Loosen the fittings on the lines to close the schrader valves, pull off the hose fittings, and check that the schrader valves aren't leaking. If they are, Auto Zone has a fix kit that includes two valves, two caps, and the little tool to install them. Always charge a vacuumed system. You can't have air in there with the freon. Hook up the manifold, do the vacuum for 15-30 minutes, then hook a can of R134 to the yellow hose. Start the car with A/C on max (recirculate), full fan. Slowly open the low side valve. The low gauge will nearly peg. Watch the high side. When it reaches about 100 psi, the compressor should kick on and cycle a few times. I charge from a 30# cylinder, but you'll have to stop a couple times and change cans. At this point, take the RPMs up to about 1500 and hold them there. Continue charging until the low side reads between 30-40 and the high side reads 250-300. Those are very generic numbers. For instance if you set up using those numbers in the winter, come summer time your high side would spike at 500 and blow a hose or damage the compressor. Once you get in that ballpark, go ahead and rev it up to 3000 or so and watch the high side. If it keeps climbing fast even though the RPMs are steady, or if it goes over 400 psi, you probably have overcharged it. Just bleed a little off while no one is looking. :) If you notice that you can't get these numbers, something is wrong. For instance, if the compressor is kicking on and the low side is spiking while the high side isn't, most likely you have a restriction in the dryer, or the compressor is failing. A spike on the high side could mean that the condenser or the expansion valve is clogged. When you're done, close all valves and unscrew the tops of the hose fittings (this will make sense when you get the manifold). Now gently unscrew the fitting on the freon can and let the freon escape from the yellow hose. The exiting freon will cause frostbite so don't let your hands linger there. Then you can take the yellow hose off the can. Now, open the high and low side valves to let the pressure escape from those hoses before you pull them off the AC lines. Some generalizations: 1-never add freon to the high side by opening the red valve 2-never add freon to a system that hasn't been vacuumed 3-topping off is an OK thing to do which lets you skip the vacuum part, but it indicates that there is a leak and it might accelerate the leak. 4-never vent R134 into the atmosphere. That's the legal thing to say. Most shops will let small amounts vent without feeling guilty. Enjoy icy cold air.

Thanks for the write-up Curtis!

I actually broke-down and went to a shop for a proper system analysis. The compressor was diagnosed as a bad component - not good.

The low-side pressure was well within normal specs (30#), but the high-side was also showing about the same number - also, not good. The compressor is making noises one that a good one shouldn't produce.

The cost of a replacement compressor (new or rebuilt) is just too prohibitive at this time, so I'll continue enduring the heat.

It's just another speed bump on the road of life.

Thanks to everyone else who offered advice and information, too!

How do I add this thread to my watchlist?

Joey

Yeah, I gotta do this on the grandparentmobile '02 taurus, I got a cheapie gauge for hte low side and it keeps going to the high pressure safety shutoff, and then going back to cycling. So I'm assuming there's either moisture in it, or a blockage..wish I knew how to track it down.

Whatever you do guys, don't put any cans of R134 with stop leak or sealant/conditioner into your system unless the next spot the car is headed for is the junkyard. It will destroy any service equipment and seize your system with resin when left open to atmosphere.

It is like giving your AC system STDs. No shop will want to touch your AC system for fear of destroying their equipment.

I had to replace an entire AC system because the PO put sealant into the car. The sealant wasn't effective enough to plug up a condenser leak so most of the resin hardened inside the system. It could have been a easy replace the condenser and dryer job, but it turned a costly repair which included the joy of ripping apart the dash to get at the evaporator.

I used to work in a shop that did A/C work and I watched talented techs scramble to find solutions. It's not that cut and dried.

So if I want to replace O rings or schrader valves, I want to have the system reclamed first right? After the reclamation is the system in a vacuumed state? Are there any safety concerns for cracking open the system once the juice is reclaimed? Any safety procedures for cracking open a system that is in the vacuumed state?

What does it mean if the compressor won't turn on? Fuses are good, yadayadayada. Is it always a fried compressor, or can dirty contacts in the switches do that? (she bought the car from her stepdad, who smokes cigars)

Assuming the control head is working properly then a very low charge can prevent the compressor from cycling. Have you tried jumping it to power and ground to confirm it works?

Tighe wrote: Assuming the control head is working properly then a very low charge can prevent the compressor from cycling. Have you tried jumping it to power and ground to confirm it works?

No, not yet. It's the g/f's truck (`93 Olds Bravada, 4.3 "Vortec"). I'm an idiot with electrical stuff, are you talking about jumping the compressor, or the control head?

I actually was considering pumping a little 134 (without the sealant) into the thing, just to see if pressure was the problem, but both pressure ports seem to be the same size (and smaller than the fitting on the refill kit I have). Gave up at that point, just in case. I sure don't want to open the HP port, just in case there's still some pressure there.

One port's on a straight line, I assume that's the LP port, since the other one's so close to the dryer..

Only manual I have is the Haynes, it's pretty much worthless in this case.

Thanks for the reply, Tighe. She's a young'un, so the heat doesn't bother her like it does me...but we've got low 90s already in Atlanta. I'd be her hero again if I can fix it for less than a hundred bucks...