Advanced auto parts has a really nice A/C charge kit in a can.

It comes with a built in pressure gauge that tells you when the charge is low, full, warning, and danger-high.

I really like it and have had much success with them.

It is so easy to use, you just follow the directions and pay attention to the gauge and you can quickly charge two or three cars with one bottle depending on how low the system is.

Since I am mobile, most of my customers want the quick, cheap easy fix, so I have been very successful with this.

Keep in mind that any low system most likely has a leak of some sort, but this works really good with the systems that still blow cold , but just need a quick boost.

I really like the idea of the gauge on the can, it takes all the guesswork out of it.

I buy the more expensive kind that has the refrigerant and gauge in one can.

Just thought I would pass it on to you do it yourselfers who want to top off your system without taking it to the shop.

I would not recommend it if you had a major leak and your system was completely empty, then you would just be wasting your money.

It costs about $34.00 and you can usually top off two or three cars with it.

They also guarantee the product for 30 days if the can is faulty and leaks out.

John.

Low-side pressure readings are better than none, I suppose, but I've never seen the need to buy a can with a throw-away gauge. On the other hand, my car tells me the high-side pressure to a resolution of 1 bar (about 15psi).

Note that Advanced (and others) sell an Interdynamics kit for about $100, with both gauges. Note also that the correct low-side and high-side pressures depend on a whole bunch of variables, including outside temperature, cabin temperature and humitidy, and vent temperature. Going from a single gauge and no chart is guesswork in the highest degree.

I would also take issue with always adding oil. I don't add oil unless I think it needs it because of a huge loss of refridgerant. Too much oil will kill your compressor. Also note that there are two types of AC oil for HFC143a systems. I'm not sure about POE oil, but the PAG oil used in the MB comes in various viscosities as well. Doesn't MB require a higher viscosity than most cars?

My bad, I said refrigerant and oil in one can, was a brain fart, meant to say refrigerant and gauge in one can.

You leave the can on long enough for the system to run as cold as it will get with fans running full blast, and you watch the gauge, the gauge stays the same at the max top pressure, you quickly blast the can, let go of the trigger and watch the gauge.

It does not fluctuate drastically and is really easy to use.
I have had great success with it and I actually learned about it from another small shop that has had plenty of success with the product.

I like it, have had great success with it.
Good product.

No oil makes it sound better. I tend to buy a few cans of 134a whenever I see it at a decent price with no additives. I'm sure I'll use it eventually.

But you should still consult the chart, even if you're only checking the low-side pressure. On my car, the low-side gets lower when the system is under a greater load, according to the chart. It would be very easy to overfill under these conditions.

But you're right that outlet temperature is a good way to get a decent guess. Just don't keep going once it gets to 40F or below.

You mentioned it cost $34. Why not spend a little more and get the complete manifold gauge set for $65 that does the same thing plus a whole lot more?... and with precision.

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95 E320 Cabriolet, 159K

I've used the same thing. Basically to get just a little bit of pressure in the system to see if the compressor will engage. Worked on my 240D and the 420SEL. I have since evacuated and filled the system properly with gauges.

These are cheap enough. I've got a couple of sets of good gauges, but I've used a friend's set of these; they worked fine. $40

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=92649

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The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)

Let me just say to the DIYs who might buy something like this....

If you do buy a manifold and use the high side gauge, BE CAREFUL. Connect the high side with the compressor NOT running. At 200 PSI or so, that refigerant can burn you in a flash!

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2012 E350
2006 Callaway SC560

I've shot a can of that stuff into my system, which the PO said had been dead for years. I had found the wires disconnected on the bottom of the compressor and reconnected them. Figured it was wortha try as the local A/C shop wanted 60 bucks to just check it out. We still got cold air....although summer is coming to Texas and I wonder if this tiny compressor will cool and keep cool this big wagon!

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Mark
1983 300TD Wagon
Even a broken watch is right twice a day

I do have a set of snap-on gauges that I use to check the sytems out before and after.

I just like the gauge on the can and I pay close attention while filling a sytem.

I just like the idea of having at least some type of overfill indicator on the can itself unlike the other product out there. Then I can hook up the gauges afterwards to see how efficint the system is operating.

Most do it yourselfers don't have a gauge set so the gauge on the can is a plus to have.

I think it is a good product.

Can you check the pressure using only the high side pressure indicator on the climate control panel?

Len
'99 E300TD 89,000 miles

Best way I can think of to get too much oil in the system.

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1989 300 SEL that mostly works, but needs TLC

I agree.

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2012 E350
2006 Callaway SC560