Auto A/C question

[imoldernu]

Can I add refrigerant myself?

Here's the situation:
Car- 1996 Cadillac SLS
In the fall, for a split second, the OBCDII came on "low refrigerant"... but went off quickly and the A?C worked perfectly.
Last month, turned on A/C... worked fine.
Last week "low refrigerant" code ... A/C shut down won't restart.

I don't trust dealer shops, and am leery about local garages, as I believe I'll get the "you need a new compressor" or "it's the evaporator", or "we need to purge the system and refill, then test again"... "Cost estimate?... we can't tell. Could be $1500 to $2500".

Now here's the situation... I love the car, but the book value is $2000, so a $1500 bill doesn't make sense... and once the garage starts any work, I'm trapped.
.......................................
The DIY option.

Local stores, including Walmart sell R134... so some people must buy it and do their own recharge. Why not me?
The first thing I always do is check on-line for how-to explanations.... and there are many to choose from. Problem is that the more "definitive" instructions give warnings, like... "use your low pressure guage to check for remaining refrigerant" ... Sheesh>>> What low pressure guage? $75 for a tool I may not need.. or ever use again?
That comment is followed by..."If you add refrigrant, and the system is empty, you will probably lock up and burn out the compressor." ... and... "it's best to let a professional do this"....

On the other hand, some sites just say... "simple... find the valve, attach the R134 can and top off the system."

Rock and the hard place... I'm inclined to do nothing, and just drive the car when the weather's not hot... I grew up before A/C, so not the end of the world. On the other hand, if I could get the A/C back for two or three hundred dollars, it would definitely be worth it.

My decision, for sure, but here's the question:
Any advice on trying it myself... suggestions for how to proceed... things to watch out for, or obvious ways to determine if the repairs would be too extensive to be worthwhile trying. And... anyone who has successfully added refrigerant themselves.

Kinda like wondering whether to repair or reroof, on a smaller scale.

 

[rbmrtn]

Can I add refrigerant myself?

I would DIY ( as I do most things ). Had a GM years ago, compressor seals leaked and recharged it every so often. Actually put 4 compressors in that car.

Here's a utube how to ( you probably already looked )

How to Recharge Your Car AC with Arctic Freeze - YouTube

Here's another howto with pretty good writeup

How to Recharge Your Air Conditioner With Freon

Might start with investigating the OBCD code first to see if it means what you think ( sometimes they can be misleading ).

 

[ERD50]

I did this recently using something that looked just like the 'arctic freeze' video. I bought it at Walmart, might be a different brand, but it has that gauge built in. Maybe $20 or something like that?

I added two cans to DD'd 1998 GM car. It lasted over the summer, but not the next spring so there was probably still a small leak. It was pretty simple by following the directions. Very easy for the second can.

We traded it in at CarMax after that, so never followed up on a longer term fix. But I'd say it's worth a try.

-ERD50

 

[martyb]

I just charged my wife's 2007 Toyota Camry's a/c a couple of weeks ago, using one of those kits in a can that I bought at the local Walmart. It wasn't the one in the video, but in a black can...don't remember the name brand, but there's a Youtube video about using it, which is really informative, plus the instructions with the can are pretty clear. Only regret I have is I didn't read the instructions all the way through to the end BEFORE I started using it...a man thing I guess. I ended up hooking things up out of sequence, and didn't shake the can as well as I probably should have. Still....apparently idiot-proof and the result is all is well and wife is happy with her now-cold a/c. I reccommend DIY for this if you're sure your system is otherwise operable, ie. the compressor etc. If it's just low on coolant, you can do it. Be sure to follow the directions closely, so you don't overcharge the system. You'll see on the gauge on the can when you're in the correct zone for charging pressure. Good luck.

Oh yeah, I think I paid around $35 + tax.

 

[NW-Bound]

The new type of R134a cans with a built-in pressure gauge is the most easy way to add Freon. It's economical and easy.

Ideally, you want to have another pressure gauge on the "high-side", meaning at the outlet of the compressor to make sure the pressure there is within range (I have such a gauge), but most of the time it is not necessary.

When the pressure is low as indicated by a cut-out pressure switch on the low side, the compressor is prevented from turning on. Do not wait too long to add Freon, as refrigerant circulation is needed to get all the seals lubricated, and to keep the small leaks from getting worse when the seals and gaskets get dried out.

 

[bjorn2bwild]

My local parts store cautioned me to not use the refrigerant with added sealant as some AC service shops will not work on vehicles afterward.

 

[eytonxav]

I think the auto industry changed to R134 sometime in the 1990s, make sure your car will accept that, otherwise it may not work well if you have the older freon.

 

[martyb]

My local parts store cautioned me to not use the refrigerant with added sealant as some AC service shops will not work on vehicles afterward.

I'm really doubting that. Not not they told you that, but that it's true. I could see A/C shops having a vested interest in car owners not being able to do their own maintenance, though.

 

[38Chevy454]

You can do it yourself. Your 96 car is R-134a refrigerant. Freon is the trade name for R-12, used in 93-earlier vehicles; although the exact cutoff changes with models and mfrs.

While the exact diagnosis over internet is not possible, the chances are your system is just low and a recharge will get you going. If you follow the line from your compressor clutch it will lead to a plug on a pressure switch - this is what keeps it from working. The pressure switch is safety so the compressor does not run dry, as the system is lubed by the oil circulating around with the refrigerant. Not enough refrigerant and you can hurt the compressor. To do it right you should have both low and high pressure gages. The can with a the gage is just low pressure. Always charge into low pressure port.

Don't put R-134a with leak sealer or with dye for leak check, just straight R-134a. If a shop decides they need the fluorescent dye let them do that. Only other caution I will give is that R-134a is much more sensitive to overcharging. So while you are charging the new can, and have the A/C set on max and engine run at about 1500 rpm, monitor the temps at the outlet. Once it bottoms out and does not get cooler, stop there. For best performance of the A/C it needs airflow over the condenser (the heat exchanger with fins in front of the radiator), so ensure your condenser is clean of bugs and leaves for good airflow.

 

[Sue J]

I did this to our 1990 Camry when we still had it. Easy and inexpensive. If I'm remembering all this correctly the car originally had the older type refrigerant and we had earlier upgraded the system to use the new stuff. All the shops say you have to be a certified tech or shop to do this but I bought the kit at an auto store or Walmart, etc and handled it just fine.

Read the directions, read online.

I saved the partially used tank (or maybe it was an extra tank) and my son used it on his 1999 Subaru Forester when it needed a recharge. Stuff was still good.

 

[NW-Bound]

There is no risk of adding R134a to an older vehicle using R12; the auto industry changed the size of the ports to make this impossible (although stubborn people can buy an adapter).

They also did the right thing this time by having the high-side and low-side ports of different sizes. Hooking up a can to the high-pressure side will cause it to burst like a grenade with serious injury or death results.

 

[bjorn2bwild]

I'm really doubting that. Not not they told you that, but that it's true. I could see A/C shops having a vested interest in car owners not being able to do their own maintenance, though.

You may be correct.
I was planning on using straight 134a anyway, so I took the advice in stride. His explanation was something like - its gums up the reclaiming equipment.
I did have two trusted mechanics say the sealers were not effective and continually adding dye was counter productive.

 

[imoldernu]

Thank you all for the input...Within two hours of my first post, I bought a kit from Walmart... $45... It came with three 10 ounce cans of 134a, a pressure gauge and some adapters that I didn't need. It also had an excellent intruction CD, which explained in some easy to understand detail, how to recharge, top off, or do a conversion from the older system... which would require a bleeding of the older refrigerant that most A/C dealers would do for free, as they could recycle the old R12... which has become extremely expensive.
.
The kit was enough for a full recharge of either the newer system, or the older Freon R12 systems. The new cans of refrigerant contain oil and sealant.

The topping off, which is what I was doing, is extremely easy. The pressure gauge is screwed on to the can, and attached to the correct input valve on the car. The pressure gauge is adjustable in that you set the gauge for the ambient outdoor pressure, and the "range" of correct operational pressures is bracketed. Shake the can... and press the lever until the pressure goes into the correct bracket.

Simple... worked....
The system took less than 1/2 can, out of the three in the kit, so I have enough left over to do your car too...

Now... one more thing. In order for the A/C to accept the additional refrigerant, the compressor has to be going. In my car, the On Board Diagnostic Center (OBDC) senses when the refrigerant is low, and to protect the compressor, shuts it off. When I first tried to add the refrigerant, the compressor wouldn't start. Though it wasn't in the instructions, I had to reset the OBDC code, so the compressor WOULD start.

So yeah... I could have done the whole thing with $10 can of R134, but it was more than worth it to understand what I was doing, and why.

The system is working better than ever. Instant cool. Just like new!. And now, even if there's a tiny leak after 17 years... I'll have enough to redo it again. I even went to my other car, and was able to squeeze in a small amount to top that off... (it was still working, but not quite as cold).

Thank you all again...!!! Great advice...

 

[Lakedog]

There is no risks of adding R134a to an older vehicle using R12; the auto industry changed the size of the ports to make this impossible (although stubborn people can buy an adapter).

I did this on a 1992 Toyota truck a few years ago - bought a kit with the adapter and had no issues at all.

 

[NW-Bound]

As I recall, they talk about the refrigerant oil used with the R12 not being compatible with R134a. This necessitates the draining and cleaning out the system before recharging with the new lubricant and refrigerant.

What happens if one simply tops off with R134a? I do not own any older car with R12, so it's academic at this point.

 

[Lakedog]

As I recall, they talk about the refrigerant oil used with the R12 not being compatible with R134a. This necessitates the draining and cleaning out the system before recharging with the new lubricant and refrigerant.

What happens if one simply tops off with R134a? I do not own any older car with R12, so it's academic at this point.

I did not drain/clean the system but it was likely very low as there was no cooling going on at all before I added the R134a. I kept the truck another couple of years and the ac was still working fine when I sold it.

 

[NW-Bound]

I searched the Web and here's an explanation. The oil must be compatible with the refrigerant so that it can be carried by the refrigerant and circulated through the system. R12 uses mineral oil, while R134a uses PAG or ester oil.

Not draining the old oil and recharging with the new lubricant may result in premature compressor failure due to lack of lubrication, they warn.

 

[Sue J]

Thank you all for the input...Within two hours of my first post, I bought a kit from Walmart... $45... It came with three 10 ounce cans of 134a, a pressure gauge and some adapters that I didn't need. It also had an excellent intruction CD, which explained in some easy to understand detail, how to recharge, top off, or do a conversion from the older system... which would require a bleeding of the older refrigerant that most A/C dealers would do for free, as they could recycle the old R12... which has become extremely expensive.

What you saved on this exercise will pay for at least the next 5 years of your membership here.

 

[Texas Proud]

Bringing back memories.... I used to do the old Freon.... had a gauge you could hook up to high or low side...


But, back then the cars had a sight glass... a small window where you could see the flow of freon... if you saw bubbles, not enough... you put in until you saw a steady flow... still, used the gauge anyhow....

 

[38Chevy454]

If you leave the mineral oil from an R-12 system in place, it is not miscible with R-134a refrigerant. So it will just sit in the low spots and be kind of like a contaminant. Without the PAG (most factory fill oil) or POE (aka ester oil, used for conversions) the compressor would not get adequate lubrication.

Your 96 car was R-134a from factory, so the top off with straight R-134a is all you needed. Don't add extra oil, most systems when they leak lose refrigerant and not much oil.

BTW, the kit you bought is intended for an older R-12 conversion, that is what the adapters are for, along with the oil can. Does not hurt to have the extra parts, only a small extra expense. Still much lower cost in the end DIY than taking it to a shop.