AC question

[Donald]

Two questions:
1) Should one consider a routine AC service, where they remove the freon, evacuate the system and then installed the proper amount of freon by weight? Or wait till something goes wrong?

2) Others have mentioned that the proper way to fill a system is to remove the freon, and refill by weight. But I would guess 20 years ago garages did not have machines that could do this, probably only at the factory. So how did a guy service an AC system back then, I assume with the high and low pressure manifold gauge? Is there a real downside to doing that today?

 

[Quest]

Don,

RE: (1), Unless your A/C system is suffering from a systematic failure such as massive refrigerant leak, component failure, etc. that would call for recovery of refrigerant, replacing of component(s), and then evacuation of the system before re-introduction of refrigerant, otherwise, you do not need to perform regular evacuation/refrigerant recovery on a regular basis as part of the routine maintenance scheme (consider the fact: so long as the system doesn't leak refrigerant and no component failure, fridges can hold their cool for decades...)

In other words: if it doesn't fail, don't touch it.

(2)Proper filling of refrigerant requires a dual gauge, scale (if you want to evacuate, recover the refrigerant and then weigh it before re-introduction, yadda, yadda...), a properly functioning vacuum pump, etc. so the answer is yes.

things are a bit different with R134a than that of R12 for R12 system is more tolerant to overfilling/underfilling, and it carries lubricating oil very, very well. For DIYers back then with R12 system, they don't need to worry too much about overfilling/underfilling and still able to keep it running nicely. However, if you do that with R134a, you may cause more harm than good.

That's why there's still the mentality of DIYers doing refrigerant recharging using OTC cans even though R134a is no longer a good DIY option.

Cheers,

Q.

p.s. if memory serves, freon is a licensed trade name for DuPont's R12, and not applicable to R134a so therefore it's best if you start referring R134a as refrigerant.

 

[brianl703]

DuPont's name for R134a is "Suva".

 

[mechtech2]

Like mentioned, there is no need to evacuate a system with a charge still in it, even if it is low.
If there are repairs and the system has been opened, then you need to start from scratch.
A DIY charge is great - you can save hundreds of $.
The directions are easy.

 

[Donald]

So the places like Jiffy Lube that offer an AC service are kind of ripping one off. They can remove and refill the R134A but cannot repair the system. If one has lost some R134A then the leak needs to be found and fixed (worn/dried out O-ring) then the AC refilled. I'd guess many people just have the system refilled without the leak being found. In NY, the Jiffy Lube places do not have a NY Vehicle Repair license, thus they can only do some simple things, like fluid change, belt and bulb replacement in addition to inspections.

 

[Donald]

Originally Posted By: mechtech2
Like mentioned, there is no need to evacuate a system with a charge still in it, even if it is low.
If there are repairs and the system has been opened, then you need to start from scratch.
A DIY charge is great - you can save hundreds of $.
The directions are easy.


But I thought the only way to properly charge a system was to remove the R134A and weigh what goes back in. One cannot weigh whats in the system without removing it.

 

[JHZR2]

please use the search. Weight is a metric but operating pressures are what it's all about.

https://bobistheoilguy.com/forums/posts/1153849/

JMH

 

[Tahoe4Life]

Originally Posted By: Donald
Two questions:
1) Should one consider a routine AC service, where they remove the freon, evacuate the system and then installed the proper amount of freon by weight? Or wait till something goes wrong?


I Live in Miami where the A/C stays on all year long..We have several cars in the family and never get the A/C serviced..My 88 Crown Vic went 10 years and over 200K miles without any service and it was still cold when I sold it in 99..My 99 went 150K miles and 7 years without any kind of service..My sister just sold her 94 Camry with 220K miles on it and had the A/C on since 94 and it was still cold when she sold it a few months ago..

If its working OK don't touch it!

BTW DON'T LET JIFFY LUBE TOUCH THE A/C..They can't even change the oil properly plus the they charge for work they don't even do..If anything they will screw up the A/C big time..For any A/C repairs I would recommend the dealer only..

The bulk of the people who have A/C problems are the ones who don't use it enough.

 

[Rock_Hudstone]

Originally Posted By: Donald
So the places like Jiffy Lube that offer an AC service are kind of ripping one off.

Changing the refrigerant in a otherwise properly functioning A/C system is like replacing the air in tires.

 

[Rock_Hudstone]

Originally Posted By: FORD4LIFE

..For any A/C repairs I would recommend the dealer only..

The dealers play the same game as Jiffy lube; run the bill up as high as possible.

Never take a car to the dealer for service unless its under warranty.

 

[Bob The Builder]

Opinions are like.....we all got em.

I have a quick question for the backyard a\c experts out there. Can one use R12 Freon in a system that originally came filled with R134a?

 

[onion]

Originally Posted By: Donald
But I thought the only way to properly charge a system was to remove the R134A and weigh what goes back in. One cannot weigh whats in the system without removing it.


If one has the equipment, then there's no excuse to do otherwise. If a system is low, and one has the equipment available, then it should be evacuated and charged by weight. Also, if a system if completely evacuated, and you know how much refrigerant it requires, you can just count up the ounces and charge via cans- works just as well. But what I'd caution against is 'topping off' a system with an unknown quantity of refrigerant... it'd easy to overcharge the system- which can cause poor performance (best case) or compressor failure (worst case). I've replaced quite a few compressors because some shade-tree thought another can of refrigerant would be 'good' for his system.

That said, if one is experienced with a/c systems, a system CAN be topped off by watching pressures and the sight glass (when available). It's a guestimate at best- and I don't reccommend it unless you work on a/c systems routinely- but you can make a system work well enough this way.

Like others here have said- if it ain't broke, don't fix it.

 

[Tahoe4Life]

Originally Posted By: Rock_Hudstone
Originally Posted By: FORD4LIFE

..For any A/C repairs I would recommend the dealer only..

The dealers play the same game as Jiffy lube; run the bill up as high as possible.

Never take a car to the dealer for service unless its under warranty.

In Florida [the biggest rip off place on earth] the independents are so bad its pathetic..My buddy took his 94 Ford C.V to get his A/C fixed last year at a A/C place and after 500 bucks and 2 months later it went out again..He took it back and they just couldn't get it right so he took it to Ford and 800 bucks later its been just fine.

The worst places to go for anything are the tire places..They will rip you off big time!!

To me any place will rip you off for something but generally the dealer gets the work done..At least they know the car better as they work on the same cars day in and day out.

 

[Chris142]

Originally Posted By: Bob The Builder


I have a quick question for the backyard a\c experts out there. Can one use R12 Freon in a system that originally came filled with R134a?
Not legally. You would need to flush out all the old Pag oil. You would need a larger orifice tube too.

Then the fun of making/ finding a way to get the R12 into the R134a fittings.

 

[Rock_Hudstone]

Originally Posted By: FORD4LIFE\
In Florida [the biggest rip off place on earth
the independents are so bad its pathetic..My buddy took his 94 Ford C.V to get his A/C fixed last year at a A/C place and after 500 bucks and 2 months later it went out again..He took it back and they just couldn't get it right so he took it to Ford and 800 bucks later its been just fine.

To me any place will rip you off for something but generally the dealer gets the work done..At least they know the car better as they work on the same cars day in and day out.

Right, Florida is riddled with hacks from what I hear.

Granted, there are plenty of private mechanics that should have never picked up a wrench, the trick is to find an honest one who knows his stuff. I suspect half the reason for your buddies failed A/C job was they may have used a cheap aftermarket compressor which have high failure rates.

The thing that burns me most about the dealers is they are notorious for gouging customers, have bad attitudes, and sometimes do a half-assed repair to boot.