Recharging AC

[Spydermag68]

Should I take my car to a shop or can I just use the can from an auto parts store?

 

[Shawn]

You can recharge it yourself but if it's low on refrigerant then it has a leak. Recharge it and see how long it takes to get low again.

Also, get one of those charging kits with a gauge and make sure not to overcharge it.

 

[IEC]

Decide for yourself if you have the skills and know-how to do it yourself. If refrigerant is low chances are it has a leak though...

 

[NoShangriLa]

I don't know the regulation in the US, but here in Canada a refrigeration or related license is require to purchase & handle refrigerant.

R12 & R22 is quite forgiving, therefore it will work if under charge or over change (workability range is almost 1 lbs different). While R134A & R410A working range is very narrow (can't remember the range for R134A but it range is similar to R410A which is 1 ounce).

Depends on what kind of work you are willing to do, but replacing gaskets will require you to pump down the refrigerant/oil (it is against regulation to vent refrigerant into the atmosphere), then add refrigerant by weight according to the manufacture spec or by pressure measurement.

IMHO, leave the work the professional if you have to ask the question. Try propane if you are well verse but don't tell the authority that I told you if caught.

 

[steppinthrax]

I've done full recharges on AC before. YOu first need to determine how low it is. If it's too low you have to vacume that systme out before recharging. If it's just not cooling as much anymore you can do a recharge with R-134a can and a hose. However, don't expect it to always work. The thing about those recharge kits is often a hit or miss. Most of the time if the car is old something else is wrong with the system.

1. Worn Compressor
2. Bad deccecant (dryer)
3. Dirty system
4. Leaky system.

 

[Rabidwerewolf]

Originally posted by: Spydermag68
Should I take my car to a shop or can I just use the can from an auto parts store?

You need to make sure what type of refridgerant your car's ac is using is the older R-12 or R-22 or is it the newer R-134a? You can't mix the two as it will lead to problems...R-134a is voilatile when mixed with R-12....,and it can lead to you tearing up your R-12 system if that is what you have. R-134a is also a smaller molecule than R-12 and will leak out of hoses that are designed to handle R-12. There should be a plate somewhere on or near your vehicle's a/c compressor that should tell you what type of system you have. Sometimes the a/c hoses will have what type they are too with either R-12 or R-134 on them. If you can't find or tell by either of those methods, you can look at your vehicles manual as well. Keep in mind, if you bought your car used and it orginally had an R-12 system, it might have been switched to an R-134a system. My 86 Nissan still has r-12, but a 63 Chevy II me and my dad purchased had a new R-134a system placed on it. You can also tell by the fittings, R-134a fittings are bigger and are like a tire stem, although bigger around and minus the threads. The R-12 fittings were screw on types with threads.

R-12 was faced out in 1996 so any new vehicles bought after 1996 have R-134 systems. If you do have an R-12 system, you will have to take it to a mechanic that has a license and tools to handle R-12 as you can't purchase R-12, but if you have R-134a, it is relatively as easy as changing your oil in your car to charge it up. Just go with everyone's suggestion and use a guage to make sure you fill it up properly. You can get kits for aroun $20 to $30 that have one can of R-134a and a guage at Wal-Mart, Autozone, Advanced Auto Parts, ect. Do not overcharge your system. Make sure you read the instructions, and it helps to have a buddy help although you can do it by yourself. If you do have a leak or a bad ac compressor, then depending on you mechanical expertise, you may have to take it to a shop. You will be able to tell if you have a leak as if it blows cold for a little while after you put in the coolant and then stops or doesn't blow as cool. If you know where your ac compressor is, you can see if you can tell if the compressor is coming on too. Car has to be running and ac on though. You should be able to see and also hear if the compressor kicks on or not. If it isn't, then you could have a bad air compressor that is the problem.

 

[NoShangriLa]

Originally posted by: steppinthrax
I've done full recharges on AC before. YOu first need to determine how low it is. If it's too low you have to vacume that systme out before recharging. If it's just not cooling as much anymore you can do a recharge with R-134a can and a hose. However, don't expect it to always work. The thing about those recharge kits is often a hit or miss. Most of the time if the car is old something else is wrong with the system.

1. Worn Compressor
2. Bad deccecant (dryer)
3. Dirty system
4. Leaky system.

Compressor can be recondition (replace seals/gaskets), but it is most likely that the seals on the rest of the system is at fault. Compressor expected life span is around 25 years but many will fail within 9-10 years due to crappy parts or contaminants.

AC system do not need a dryer to function, but it doesn't hurt to have one to help clean out the residue just in case the vacuum process didn't do it job or is use as a storage tank.

Another problem could be is wear out of faulty condenser.

 

[travisray2004]

Thank you guys for this intel. I now know that I have a R-12 system because all of the fittings for the R-134a, doesnt fit my system. Ironic, i now have to convert to have cool air.

 

[Rabidwerewolf]

You don't necessarily have to convert your R-12 system to and R-134a system if the only problem on your vehicle is that the R-12 is low. There are still shops that will recharge an R-12 system. I do know that R-12 is more expensive now, and at last price check, I think it is around $20.90 per pound. It will still be cheaper than converting over to an R-134a system.

However, if you have a leak, or compressor going bad, ect., then you might want to look into it converting over to a R-134 system. Either way you are going to have to take the vechicle into the shop.

 

[Shawn]

Originally posted by: Rabidwerewolf
You don't necessarily have to convert your R-12 system to and R-134a system if the only problem on your vehicle is that the R-12 is low. There are still shops that will recharge an R-12 system. I do know that R-12 is more expensive now, and at last price check, I think it is around $20.90 per pound. It will still be cheaper than converting over to an R-134a system.

However, if you have a leak, or compressor going bad, ect., then you might want to look into it converting over to a R-134 system. Either way you are going to have to take the vechicle into the shop.

Most shops won't recharge with R-12 less you get the leaks fixed.

 

[BD2003]

I've been wanting to do this since summer started on my 00 Celica. Its not cooling as well as it should, and I can see from the bubbles in the viewport that it needs some more R134. Normally I'm all over DIY, but I've been told if I were to pull the wrong hose (the high side) it would pretty much blow up in my face, and thats not good.

Any truth to that?

 

[steppinthrax]

Originally posted by: Rabidwerewolf
You don't necessarily have to convert your R-12 system to and R-134a system if the only problem on your vehicle is that the R-12 is low. There are still shops that will recharge an R-12 system. I do know that R-12 is more expensive now, and at last price check, I think it is around $20.90 per pound. It will still be cheaper than converting over to an R-134a system.

However, if you have a leak, or compressor going bad, ect., then you might want to look into it converting over to a R-134 system. Either way you are going to have to take the vechicle into the shop.

Also if you convert a R-12 system to R-134a you have to replace a lot of seals and gaskets. Partly because the old seals are not compatible with the oil the R-134a uses. I believe one uses Ester oil while the other uses PAG oil. So if you convert you got to flush the system at least. If you just convert without changing seals be ready for leaks in the future.

 

[Pacfanweb]

What year is your car? I think that starting in 1994, all cars in the US were R-134.

If you have R-12, then you need to convert it to R-134....unless you know someone who still has some R-12...and if a shop still has any R-12, it will NOT be cheap.
You don't want to bother putting expensive R-12 back in there until you fix the leak.

Now...if you have 134, here's the deal: Does the A/C cool at all? If so, then a adding a can or two of 134 will likely fix that. After that's done, see how long it takes for it to stop cooling again. (how fast it leaks out). It may well last quite awhile, and if it does, I'd just keep recharging as long as it's no more than twice a year.
If it leaks out any faster than that, get it repaired first.

Converting to 134...pretty simple in most cases. Sometimes, it's as simple as putting on the new fittings, evacuating the system, adding new oil, and charging. Even if the kit says you don't have to, I recommend changing the accumulator. (receiver/dryer to some folks).

Some specifics on your car would have helped..............

 

[Pacfanweb]

Originally posted by: steppinthrax

Originally posted by: Rabidwerewolf
You don't necessarily have to convert your R-12 system to and R-134a system if the only problem on your vehicle is that the R-12 is low. There are still shops that will recharge an R-12 system. I do know that R-12 is more expensive now, and at last price check, I think it is around $20.90 per pound. It will still be cheaper than converting over to an R-134a system.

However, if you have a leak, or compressor going bad, ect., then you might want to look into it converting over to a R-134 system. Either way you are going to have to take the vechicle into the shop.

Also if you convert a R-12 system to R-134a you have to replace a lot of seals and gaskets. Partly because the old seals are not compatible with the oil the R-134a uses. I believe one uses Ester oil while the other uses PAG oil. So if you convert you got to flush the system at least. If you just convert without changing seals be ready for leaks in the future.

Not necessarily true. Fords, for example, already had the correct seals the last year or two before they switched to 134. A flush isn't necessary in most cases, either.
Follow the instructions on the kit...if it says flush, do it, but I've not seen one yet that does.

 

[Pacfanweb]

Originally posted by: BD2003
I've been wanting to do this since summer started on my 00 Celica. Its not cooling as well as it should, and I can see from the bubbles in the viewport that it needs some more R134. Normally I'm all over DIY, but I've been told if I were to pull the wrong hose (the high side) it would pretty much blow up in my face, and thats not good.

Any truth to that?

You don't "pull a hose". There are two fittings...high side and low side. I will just say that you don't want to charge the high side.

On R-12 systems, the high and low were different sizes. Not so with 134.

To find the low side is easy: Look at your condenser in front of the radiator....follow the two lines that go from it...one of them will have a place to hook up A/C gauges...that is the HIGH side, don't charge it.

The Low side is in a line that goes to your accumulator, or receiver/dryer..usually located over where the lines go through the firewell to the evaporator. That's the one to charge. Very easy.

Another way: If your A/C cools at all, the high side will be hot, the low side will be cool. That simple.

 

[BD2003]

Originally posted by: Pacfanweb

Originally posted by: BD2003
I've been wanting to do this since summer started on my 00 Celica. Its not cooling as well as it should, and I can see from the bubbles in the viewport that it needs some more R134. Normally I'm all over DIY, but I've been told if I were to pull the wrong hose (the high side) it would pretty much blow up in my face, and thats not good.

Any truth to that?

You don't "pull a hose". There are two fittings...high side and low side. I will just say that you don't want to charge the high side.

On R-12 systems, the high and low were different sizes. Not so with 134.

To find the low side is easy: Look at your condenser in front of the radiator....follow the two lines that go from it...one of them will have a place to hook up A/C gauges...that is the HIGH side, don't charge it.

The Low side is in a line that goes to your accumulator, or receiver/dryer..usually located over where the lines go through the firewell to the evaporator. That's the one to charge. Very easy.

Another way: If your A/C cools at all, the high side will be hot, the low side will be cool. That simple.

So, out of curiosity, what would happen if I did recharge the wrong side?

I think I've figured out where the actual fitting is, down near the firewall. So just to fill it back up again, its pretty much as simple as hook the charge kit w/ gauge up to it, and squeeze it in spurts until the gauge reads green and the bubbles in the viewport go away?

 

[Zenmervolt]

Originally posted by: BD2003
So, out of curiosity, what would happen if I did recharge the wrong side?

Can of refrigerant explodes, embedding pieces of shrapnel in your skin and anything else exposed.

ZV

 

[Pacfanweb]

Originally posted by: Zenmervolt

Originally posted by: BD2003
So, out of curiosity, what would happen if I did recharge the wrong side?

Can of refrigerant explodes, embedding pieces of shrapnel in your skin and anything else exposed.

ZV

Yep. Other than that, not much will happen.

 

[Pacfanweb]

Originally posted by: BD2003

Originally posted by: Pacfanweb

Originally posted by: BD2003
I've been wanting to do this since summer started on my 00 Celica. Its not cooling as well as it should, and I can see from the bubbles in the viewport that it needs some more R134. Normally I'm all over DIY, but I've been told if I were to pull the wrong hose (the high side) it would pretty much blow up in my face, and thats not good.

Any truth to that?

You don't "pull a hose". There are two fittings...high side and low side. I will just say that you don't want to charge the high side.

On R-12 systems, the high and low were different sizes. Not so with 134.

To find the low side is easy: Look at your condenser in front of the radiator....follow the two lines that go from it...one of them will have a place to hook up A/C gauges...that is the HIGH side, don't charge it.

The Low side is in a line that goes to your accumulator, or receiver/dryer..usually located over where the lines go through the firewell to the evaporator. That's the one to charge. Very easy.

Another way: If your A/C cools at all, the high side will be hot, the low side will be cool. That simple.

So, out of curiosity, what would happen if I did recharge the wrong side?

I think I've figured out where the actual fitting is, down near the firewall. So just to fill it back up again, its pretty much as simple as hook the charge kit w/ gauge up to it, and squeeze it in spurts until the gauge reads green and the bubbles in the viewport go away?

Yes. I'd go more by the gauge than the bubbles.

 

[Zenmervolt]

Originally posted by: Pacfanweb

Originally posted by: BD2003
I think I've figured out where the actual fitting is, down near the firewall. So just to fill it back up again, its pretty much as simple as hook the charge kit w/ gauge up to it, and squeeze it in spurts until the gauge reads green and the bubbles in the viewport go away?

Yes. I'd go more by the gauge than the bubbles.

Remember that the pressures are different at idle too. The spec low-side pressures for my 951 are listed at 1,500 RPM so you might want a helper to rev the engine a little bit and check that the guage stays in the green area at 1,500 RPM too. The green zone should be large enough that it covers both idle and 1,500 RPM pressures.

ZV

 

[BD2003]

Things I learned today:

1. Toyota engineers are looking out for the little guy - the cap on the low side literally has an L on it, and the high side has an H.
2. R134 is really, really cold. Not liquid nitrogen, instant frostbite cold (I know from experience), but its pretty damn cold. In retrospect, this should not be surprising to anyone.
3. Yet another simple thing that I don't have to pay someone $100+ to do for me.

I didnt have a helper nearby to rev it for me, but I filled it towards the top end of the green area (about 42psi). It started out at the very bottom of the green end. I thought the can was empty (it felt lighter) and it didnt seem to be recharging any further, but I found out the hard way it wasnt when I took the gauge off the can. Whoever designed the kit I bought (arctic freeze) appears to be a bit of a retard though....the gauge was upside down.

Anyways, its maybe subjectively a little chillier (although that could be just placebo). Theres still quite a bit of bubbly action in the viewport though, and I feel like it should be colder. Is it worth it to reattach everything and go for it again when I have someone to rev it?

Should pressures drop or raise when it revs?

 

[Zenmervolt]

Originally posted by: BD2003
Should pressures drop or raise when it revs?

Low side pressure will drop, high side pressure will increase.

The can will stop filling when the pressure in the can and the pressure in the line equalizes, so there will still be some residual pressure in the can when you disconnect.

ZV

 

[db]

If I recall correctly, up to 1 oz leakage per year is considered normal. If your system is charged with one can of the correct refrigerant you just might be lucky and it will cool satisfactorily.

 

[Pacfanweb]

Originally posted by: db
If I recall correctly, up to 1 oz leakage per year is considered normal. If your system is charged with one can of the correct refrigerant you just might be lucky and it will cool satisfactorily.

This is true, even more so these days. No A/C system is completely sealed. After a few years, many cars need a little shot of refrigerant, but you really can't find a detectable leak.
Not uncommon at all.

 

[Spydermag68]

Does anyone know where the low pressure side is on a Chevy Blazer?