Engine Size: 2.0
Refrigerant Type: 134a
Ambient Temp: 84
Pressure Low: 63
Pressure High: 112
Country of Origin: United States
A/C suddenly stopped blowing cold air. Put cheap aftermarket charging hose w/gauge on it first, said charged, showed blue zone for ok. Not satisfied w that, I put my mastercool gauge on & got some bizarre readings.
1st reading, engine & comp off - gauge valves closed, reading L=63 H=112.
2nd reading, engine on A/C not on yet - opened low side valve on gauge, reading L=25 H=125. Pressure Line too hot to touch/hold, not temp hot or cold to touch on low line.
After checking all connections fuses etc, took readings again, L=26.5 H=0. Thought that reading was strange, removed gauges made sure lines on it were purged, valves closed, hooked back up reading 0/0. Started engine & A/C, reading 0/0. WTF? My gauges crap the bed or what?
Put cheap aftermarket hose back on, gauge still says charged/ok, but showed a slightly lower pressure then the first time I checked it with that one. Totally frustrated I call dealer & ask questions, figuring it must be a blockage in the system, so it may be covered under warranty due to a part failure, so I bring it in tomorrow 7/11.
Service dept tells me that MOST cars USUALLY need an Evacuation & Recharge every 4 to 5 years. Anyone ever hear of this before? If so, is that the usual Life Expectancy of 134a?
Life expectancy of R134a? Forever. Really. It doesn't get used up in the AC system. It just goes round and round. Those Walmart gauges are pretty much junk. Can't really trust that. Also can't go by pressure alone to know if you are charged properly.
1st reading: The system had been operating and the pressures haven't yet equalized. Nothing strange here.
2nd reading: You opened the valve on the gauge manifold? I'd guess that now you have just vented all your R134a to the atmosphere. That explains the 0/0 reading you saw next.
Now you will need to properly evacuate and recharge before you can begin to figure out what was really wrong before you started.
Recovery of the existing refrigerant is common to measure how much is in there. Do add some additional to bring it to proper level, then put if all back again. Has nothing to do with the life of the refrigerant.
But appears to me, playing with that can of crap, you may have contaminated your system, not only with that leak stuff, but also with air and moisture. Are you going to hold your dealer responsible for that?
If he is smart, he will know you played with it. Happens to me every once in awhile, can only say, if you want me to repair it, its going to cost you extra, or just leave.
First some manifold 101. The valves on the manifold remain closed at all times except to add or remove stuff through the center (yellow) hose. The gauges are connected directly to the red and blue hoses before the valves so they always show the pressure in the hoses even with the valves closed. Like fix_it said, opening a valve without anything connected to the yellow hose is likely to let the refrigerant escape.
If your manifold's service port couplers have knobs on the top, the knob moves the valve pin up and down. First be sure the knob is fully counterclockwise so the pin is retracted, then pull up the locking ring and couple onto the car fitting. Once it's locked on, turn the knob clockwise to extend the pin, which will open the shrader valve in the car and let refrigerant flow to the gauge. Uncoupling is of course the opposite, turn knob ccw first to close the shrader valve, then uncouple.
Reading 125 / 25, no cooling, discharge hose gets very hot, all point to a serious undercharge-- i.e. it had leaked out. If you really did open the system to the air and vent it to a zero pressure (it's not just measurement error from using the couplers improperly), air has likely moved in so it needs to be evacuated first before recharging. Expect it to continue to leak, so put in some UV dye or check immediately with an electronic leak detector and find the leak.
Preventative maintenance on an auto A/C system is all external, such as checking the belt and cleaning the air side of the heat exchangers. There is no need to do anything with the refrigerant as long as it is working properly. Refrigerant doesn't wear out, it only needs replacing if it has leaked away.
If you take it to the dealer now, they see zero pressure and don't know anything else, with any luck they will just find the leak (seems that there is a pretty big one, to go from OK to no cooling in a week) and fix it under warranty for you.
Edited: Thu July 11, 2013 at 10:00 AM by mk378
I run nitrogen in my bicycle tires. Which I run tubeless and swear it allows the sealer to last longer and not ball up. Plus it sounds cool compared to the other kids on the block.
Evacuate/recharge every 5 years.....even I know thats dumb advice. Nitrogen? Dealer told me its better cuz its biger molecule, so leaks out slower. Sheesh, the difference in the 2 is sooo small- anyone who took (and passed with a B or better) high school chem knows that nitrogen is right next to oxygen- size difference is so small. I told her no.
beware of the arrival
My assumption with all this crap on the market for refrigerants and with AC problems, would be to recover, check for impurities, and learn how much was in there. Sure GMtech and iceman would go along with this.
Seems like other assumptions, is the system is working perfectly well, but told to change the refrigerant anyway, because it worn out. This is a bit crazy.
Nitrogen is always used in large aircraft tires for a number of good reasons as opposed to air. But not talking low pressure tires in automotive with maybe a mere 1,000 pound load and driving at 55 mph. Super high speed, extreme pressures, with many tons of load per tire.
For one thing, nitrogen can be viewed as treated air, removes all the oxygen and moisture, former is combustible with super hot temperatures, later will boil at a mere 212*F causing severe pressure changes. Former is also an oxidizing agent cause corrosion in valves an aluminum. For smaller airports, nitrogen is more convenient to use when you need 500 psi of pressure, try finding an air compressor that can give those kinds of pressures. Moisture also freezes in super subzero temperature aircraft experience. Nitrogen is an inert gas, air is not.
Know what you are talking about before posting.
I still say "never trouble trouble until trouble troubles you". Not quite the same as a radiator coolant flush, or ATF change....
It is totally understandable...not to trouble trouble....but when AC trouble arrives....it normally arrives with a very severe repair order also. The process of simply extending the possible repair by a bi annual service far out weights the downside. With the very short charge of todays cars, a slight leak can often result in early demise of the compressor. Consider that the cost factor to replace this unit and complete the system service may exceed several thousand dollars......well...nuff said. You're gonna pay the piper...one way or the other. Save the money...service the AC as one would any other system in the vehicle.
All this being said...they typical auto owner does not even think of AC system service....not until the system fails or stops cooling......mmmm....is that the sound of dollars hitting the cash register....why yes it is....thank you very much Mr. Customer....remember, when an offer was made to service your system for $@#%.00. and you felt you were 'being taken advantage of'.
Thankfully systems are not serviced as they should be...thus our sales tend to increase each year........gotta love it.
The strongest reason for the people to retain the right to keep and bear arms is, as a last resort, to protect themselves against tyranny in government.
Contrary to a statement above, Nitogen is not an inert gas. It reacts with a number of elements.
Nitrogen won't react with the materials and conditions found inside a tire though so it can be considered "inert" for that application. The gases in the last column of the periodic table have been found to engage in chemical reactions under very extreme conditions, so they are not properly called "inert" any more either. They are now known as the "noble" gases.
I can go along with iceman on this issue, but not the R-134a, but that PAG exposed to high temperatures that will break down.
There was a time when refrigerants were isolated from the lubricants in MVAC, should have stuck with that concept. And mixing the fluids with the refrigerant has only one powerful effect, reduced cooling.
Can you imagine using an air compressor that mixes oil with air? Same principle, except you will be spray painting with oil.
Still say they should advertise, if you want problems, we have problems. Lots of them.
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