A/C recharge?

[Jolbaru_LGT]

Is Air Conditioning recharge a doable DIY project? Or, best left to a shop or dealership?

[Max Capacity]

Shop.

 

Is there a issue you’re having after it runs for a while on a hot humid day?

[Jolbaru_LGT]

Shop.

 

Is there a issue you’re having after it runs for a while on a hot humid day?

 

 

No, I know it's been like, 3-4 years since it's been done last, and it just feels weak. It's not ice cold like it was last year.

[DaveWaters]

You could try one of those recharge kits they sell at the auto parts stores. You may have a very slow leak somewhere.. Whenever one of my cars starts getting a bit warmer, I top it off with a kit and it generally holds for a year or two. You could even buy one with uv dye so if it gets warm again right away a black light will help you find the leak.

[08SpecB_DE]

Shop.

 

Have them evacuate the system, pull a vacuum, check for leaks and then refill. If they say the system was full, it may be time to replace the expansion valve and desiccant bag.

[apexi]

I kind of went through this last year. I wouldn't do it again, but it was kind of nice to learn.

 

I replaced my condenser since it was regularly leaking oil or something from where the dissecant bag is. (https://legacygt.com/forums/attachment.php?attachmentid=257359&d=1509229873)

For $60, I decided to just buy a whole new condenser that comes with a new bag, and I also wouldn't have to worry about potentially using the wrong o-ring on the plug, assuming I could even remove the plug. (I couldn't once I got the old condenser off the car, I didn't break out the impact, but I was worried I'd strip the plug with how tight it was.) Also, I'm very happy with the quality of the TYC condenser I got, it seems nice to me, but I'm no expert.

 

Anyway.. To do the job right, I don't think you're that far off from what a shop would charge to do the job professionally.

 

My expenses, yours might be different.

- Harbor freight manifold gauge set, I think $50 with a coupon.

They also have cheap hoses or cans with 1 gauge which measures the low pressure side, but from what I understand you really need a gauge reading the high pressure side to do the job properly, and make sure everything is okay.

 

- 1 12oz can of plain refrigerant, nothing added, $5? (more on this later.. I should also mention I've read bad things about stop leak, that's why I went with plain stuff.)

- 2 cans of pag oil recharge, $14?

- 1 can of uv dye charge, $8?

edit: I forgot to mention I was lucky enough to rent a vacuum pump from autozone, otherwise that's at least $80 I think

 

 

Now, you can also get pag oil in a bottle, and dye in a bottle, or refrigerant with dye and oil in it. Since our cars take 13-15oz of refrigerant, and the oil and dye charge cans have refrigerant in them, I tried to make up the extra 3oz of refrigerant that way. (You may lose a little refrigerant when you purge the air out of the manifold gauge set too, that may be why I think I'm still undercharged). I forget the exact numbers, I looked up the msds for each product, and it seemed like I'd be in the clear at around 15oz. I actually bought a bottle of pag oil too for the o-rings I replaced when installing the new condenser, that was around $10. So it was kind of dumb to do the pag recharge, but it seemed safer than potentially overcharging with a second can of refrigerant.

 

I already have a postal scale that I used to measure the weight of the r134a can before, and after I filled the system, to see how many oz went in.

 

The factory service manual is also very specific about what the temperature should be when reading the ac system pressure, I think 86F -95F. If the outside temperature is different, your target pressures will be different, and when I looked at charts none of them seemed accurate for our car. The charts had different pressures listed compared to what subaru lists from 86-95F, so you could probably calculate them yourself, but math never was my best subject.

 

After all is said and done, I'm still rocking a center vent temp of about 48F with recirc on, and I think it's even higher with recirc off, not good. I think my system is undercharged, but didn't care enough to keep messing with it last year.

 

So all and all, I guess for me it's frustrating not being able to know exactly how much refrigerant is in my system, compared to a machine that is much more accurate and does everything for you.

 

Example of how it might be done with a machine.

 

Anyway, that's how I stumbled through my first time every messing with an AC system. More experienced guys might laugh, but I just wanted to share my experience.

 

*wow, sorry for the length and if it's hard to read, I'm not with it today.

**One more small thing in case someone comes across this searching in the future. Don't be surprised if subaru gives you black AC o-rings that may not come in a bag, they're legit, I don't know why they're not green like aftermarket ones. I had to go to subaru for one of the condenser o-rings because I had trouble finding it in aftermarket kits and at auto parts stores.

Edited May 7, 2019 by apexi

[Max Capacity]

Shop.

 

Have them evacuate the system, pull a vacuum, check for leaks and then refill. If they say the system was full, it may be time to replace the expansion valve and desiccant bag.

 

 

Yep, put the money for the can of stuff at the auto parts towards the cost of having a Pro do it right the first time.

[whitexc]

Ehh, I do the redneck recharge on my pickup yearly. One can makes it cold and lasts the season. It may be an o-ring....it may be something much more spendy. Not into spendy for as little use as the ac gets. Just me and the old truck. If it were the LGT, I may pay to get that fixed.

[Holla]

I agree, take it to a shop. I screwed around with mine last year and ended up paying the man anyway. This is a good reminder to make sure mine is working again this year before it gets super hot.

[seanyb505]

A rock punctured my condenser a few years ago. I bought the gauges, vacuum pump and correct refrigerant. Couple hours later, good to go. I knew what the problem was so I wasn't chasing down leaks or problems. Saved a bit of money, learned a bit, and have tools to do it again.

[Stphnhrrng]

Can I ask why everybody is saying to take it to a shop? I’ve recharged A/C systems before (On a Ford and BMW) and it wasn’t difficult. Is it really complicated doing it on a Subaru or something? I don’t have any leaks, I just need to charge my system since it all drained when I pulled my engine

[Marvick08GT]

If you have a vacuum pump and gauges you can do it.

[blackobxt]

You can do it but depending where you live will effect the outcome. I’ve repaired and charged a TON of ac’s and even have a few certifications in industrial refrigeration. This is the most finicky ac I’ve ever dealt with but I didn’t notice it till I moved to the desert. Everything except my evaporator is new and if you aren’t dead on on the weight the ac will cycle to the point of almost being ineffective. If you live somewhere that only hits like 95° you can probably do it yourself with a harbor freight manifold and a vacuum pump.

 

I have a theory that the evaporator temp sensor and the window it works with limits the effectiveness in high heat

[JmP6889928]

Black or dark colored cars have a harder time with A/C than white or light colored cars do too. They absorb the heat more and the A/C has to work harder to keep it cool in blazing sunlight and high temperatures. I painted the roof of my dark blue minivan white years ago, and it made a HUGE difference in how effective the A/C worked. A friend of mine in a school bus garage told me to do that and that's the reason why school bus roofs are painted white.

 

 

Now I just look for white or silver minivans when it's time to buy one..LOL. That way, it's easier on the A/C.

[Stphnhrrng]

If you have a vacuum pump and gauges you can do it.

 

I have gauges, what’s the vac pump for? to clear all the old stuff out? Don’t you just hook up a can to the gauge and fill it till you get to the correct pressure? (With the correct oil obviously) Also I read somewhere to use PAG46, and read somewhere else to use some Denso 8 or whatever it was called. I’m not sure which one is correct. I was going to have Subaru do it but they wanted just under $300 to charge my system.

[apexi]

Denso ND8 and pag46 are the same

"DENSO uses ND-oil 8 for its R134a type refrigerant compressors, a PAG 46 oil." https://www.denso-am.eu/media/corporate-news/2017/august-2017-newsletter-compressor-oil-and-refrigerant-mixing-old-and-new/

 

(I'm still a bit of an AC newbie) After the old stuff has been removed, a vacuum pump is used to remove any moisture/water that may be in the system, from humidity, anything. It's also used to help check and make sure there are no leaks, if your system is able to hold a vacuum when the pump is turned off. I think I've heard that's not the best way to check for leaks, but it's one way.

[Stphnhrrng]

Denso ND8 and pag46 are the same

"DENSO uses ND-oil 8 for its R134a type refrigerant compressors, a PAG 46 oil." https://www.denso-am.eu/media/corporate-news/2017/august-2017-newsletter-compressor-oil-and-refrigerant-mixing-old-and-new/

 

(I'm still a bit of an AC newbie) After the old stuff has been removed, a vacuum pump is used to remove any moisture/water that may be in the system, from humidity, anything. It's also used to help check and make sure there are no leaks, if your system is able to hold a vacuum when the pump is turned off. I think I've heard that's not the best way to check for leaks, but it's one way.

 

Sweet, thank you!!