Automotive a/c recharge kits.

[Donald]

Originally Posted By: Vikas
Assume you have ten year or older car. Over the years, the refrigerant has gone down. If that is the case, you have no fixable leak. Then you can go ahead and add little bit at a time. Don't be greedy and stop adding as soon as you find adequate cooling.

On the other hand if your A/C was working great and suddenly you find it is not working good any more, you have a leak and that will need to be fixed. Take it to professional.


The A/C system is 100% closed. There should be no leaks. If the freon leaked out in 10 years, it probably all leaked out over the past 6 months due to a o-ring that is no longer sealing. The o-rings should be replaced.

 

[zzyzzx]

As long as you are using r134a with no additives and at least a low side gauge, you should be fine, as long as you don't overfill it.

 

[TFB1]

Originally Posted By: Vikas
Assume you have ten year or older car. Over the years, the refrigerant has gone down. If that is the case, you have no fixable leak. Then you can go ahead and add little bit at a time. Don't be greedy and stop adding as soon as you find adequate cooling.

On the other hand if your A/C was working great and suddenly you find it is not working good any more, you have a leak and that will need to be fixed. Take it to professional.


This^^^

Unless it's suddenly dumped all the the charge, I'm gonna add refrigerant till it cools properly and then use it to see what happens... There are thousands of systems out there that leak a ounce or two per year, a occasional top off every two or three years is no big deal...

 

[Vikas]

As long as you don't overfill! We had few examples right here when somebody followed "more the better" principle and almost killed his A/C!

Assuming the cost of a can or two is affordable and one needs it only after few years, I say it is still cheaper than a visit to professional on a old car.

Try it once and if it leaks out, then you need to fix the leak and get professional involved.

 

[TFB1]

Originally Posted By: Vikas
As long as you don't overfill!


Very true... I have gauges and watch pressures...

If the system is just a little short on refrigerant, generally charging till the compressor stops cycling with the blower on a med/high speed will 99% of the time give satisfactory results... This does assume ambient is above 75*F, as on a cool day or not enough flow across the evaporator(low fan speed) even a properly charged system will likely cycle...

 

[Chris142]

Originally Posted By: LScowboy
Originally Posted By: Chris142
We need a high side guage to properly charge or diagnose an R134a system.


If he is lucky and his car uses an expansion valve, as opposed to an orifice tube (most imports use an expansion valve), then he has a good chance of having a sight glass on top of the dryer, if there are bubbles in the sight glass, then he is VERY likely low on refrigerant and topping it up until there are no bubbles, while not optimal like having a high side gauge, would likely work in a pinch.
Wrong! The sight glass worked with R12 systems but is utterly useless with R134a systems as a fully charged 134 system will still have bubbles in the glass.

 

[Kestas]

I have three basic specialty tools I use for a/c work - manifold gauges, vacuum pump, and a thermometer for the vent. With these tools I can do pretty much anything related to automotive a/c.

 

[lenjack]

If you need to add refridegerant, you probaly need to add compressor oil as well. i beleive some cans of 134a do have oil in them.

 

[Colt45ws]

Originally Posted By: Vikas
As long as you don't overfill! We had few examples right here when somebody followed "more the better" principle and almost killed his A/C!

I dont know about anybody else, but what I was doing was going by Ford pressure charts and putting enough in to bring it up within the bottom end of both the discharge and suction pressure ranges for the ambient I was dealing with. I have no idea why it wanted so much more than what it needed. I didnt have a problem doing it that way before; I had done it 3 or 4 times prior with no issues and perfect working operation. Its possible my ambient was lower than what I was reading, but I really have no idea.

I would be careful about filling it up until the compressor stops cycling. If I had done it that way, I probably would have been adding refrigerant until the accumulator filled up and slugged the compressor.
Maybe not, buuuut....
While my car has a low pressure cutout switch, its not the primary way that it cycles. Its only a undercharge protection. It uses Evaporator air discharge temperature to determine cycling of the compressor. It pulls in the compressor at 40F and lets it out at 36F.
No one knows why they did it that way; only 2003-2004 are setup that way then the 2005+ went back to the conventional method.
But I would verify any vehicle does not use some non-standard way to cycle the compressor before I did something like that.

 

[RobertISaar]

cycling is also going to be compressor dependant.... for example, the harrison V5 units GM used on a LOT of stuff from the late 80s to early 2000-ish cars don't cycle unless there is something seriously wrong(far overpressure or far underpressure), since they deal with load internally.

 

[Colt45ws]

Originally Posted By: RobertISaar
cycling is also going to be compressor dependant.... for example, the harrison V5 units GM used on a LOT of stuff from the late 80s to early 2000-ish cars don't cycle unless there is something seriously wrong(far overpressure or far underpressure), since they deal with load internally.

Yes, I believe those are variable displacement, so the compressor is changing its output to suit the conditions rather than cycle the clutch. As you said, only if you get really out of where it should be as far as charge to where it can't compensate will you see it cycle.

 

[babyivan]

I had a beater Ford Focus that I bought a can of Autozone R134 and it gave me nice A/C for the summer. I sold it right after, so I have no idea if it leaked out; but since it was low and needed it in the first place, I'm guessing YES.

I didn't take any type of pressure readings, just added a can blindly and it did the trick

 

[antiqueshell]

We have one of those [censored] Ford scroll compressors on my Dad's 2005 Ford Five hundred sedan.

The thing sprung a leak at the compressor shaft seal about a couple of years ago, and rather than replace it we have just had the thing vacuumed and recharged. It is a pretty big leak too. You can see the oil flowing out of the unit.
What junk.

Ford really screwed many customers with that compressor they had TONS of failures...I would bet that the failure rate is 75%+ after just 7 years on the road of all Ford cars that had these.