Well the temperatures are rising and the Aeros A/C isn't working too well.

Its a R134a system mechanically the system seems ok the clutch engages and disengages and the accumulator pipe is barely cool I can feel its lower then ambient temperature but not much cooler. I do feel some cold air from the vents its really not much. The system also works alot better at night when its cooler.

The refrigerant charge is ok so I'm thinking the fan clutch is preventing the condenser from getting cooled as well as it should.

If it is the clutch is there anyway to check to make sure its bad since I know its going to be a pain to get it off even with the tools.

I haven't touched it yet but would the system benifit from adjusting the screw on the pressure switch on the accumulator?

Thanks for any help you can offer .

 

If you can hear the compressor cycleing, then the clutch is ok., but if you only hear a click, and the compressor is not running, then the clutch will not be ok. How did you deduce that the charge is ok? Did you test the system with a manifold guage set? You need to measure the outside air temperature. If ithe temperature is 80 degrees just in front of the acumulator, the pressure should be over 160 psi on the high side. The low side pressure, or the pressure of an uncharged system is irrelavent, since the most important thing is that the pressure is highenough on the high side to allow efficient cooling. My guess, is that if the AC is working at all, the clutch is mostly likely working, and that your problem lies elsewhere. Do not assume what the problem is, there are tools to test just about everything. Sometimes adjusting the screw can improve performance, but do so only if you have a manifold guage set, and c an monitor the pressures on both the low and high side. Too high a pressure on the high side can rupture a hose or damage the compressor. Too low on the low side, and the evaporator may ice up, and the compressor can be damaged from starvation of refrigerant and lubricant.

 

Since your 'Star came with R134, then the adjustment screw on the pressure switch should be set correctly for that refrigerant, unless someone messed with it. I would leave it alone.

BTW: I just found out at my friendly AZ that these pressure switches do come in different flavors. For my 91 there is one for R12 and a different one for vehicles that have been converted to R134. Prob the same switch, just set at the right pressure for the refrigerant.

I don't know how to test a fan clutch, but I now have a foolproof, easy way for its removal. On my 90, with the belts on, all I had to do was put a big adjustable wrench on it, tap it with a hammer and it spun right off. On my 91, however, different story. Tried for a long time to remove it and couldn't. A neighbor came over with a small pipe wrench and slipped it over the lip of the pulley from the back (handle of wrench is now parallel with the grooves in the pulley). Held the pulley with that and a couple of taps with the hammer on the adjustable and off it came.

If your a/c clutch is cycling on and off, it is an indication of low pressure, low refrigerant. I did read on a website for Freezone or Freeze12, that you could use a thermometer in the a/c outlet to charge up your system to the proper pressure. Stick the thermometer into the vent and charge your system about an ounce or two at a time. Watch the temperature; it should continually go down as you increase the refrigerant. When the temp stays at the same level or slightly increases after adding the ounce or two of refrigerant your at the right level.

 

Cycling on/off is normal with a properly charged system. At moderate temperatures (around 70-75 degrees) it should cycle approximately 3 times a minute - give or take. At high temps, above 90 ambient, it rarely cycles.

If you suspect the fan clutch, an easy way to tell is to spray the condensor core with a garden hose when the system is warm. If this causes the high pressure side to drop quickly or you can feel much colder air out of the vents, then the fan clutch is not pulling sufficient air. A bad fan clutch is masked at highway speed due to the 'ram air' effect. Its low speed/idling situations where it really shows up.

 

Well upon using Aeros hose trick it yielded no results so I put a 14 Oz can of R134 in and the system is back to normal blowing nice cold air and the accumulator has nice condensation on it in the 90 degree heat.

My question now is is it normal for a system to lose a little refrigerant over the years little by little?

The A/C on the Aero has not been touched or worked on since it was filled at the factory and that was back in 96. The vehicle currently has 52K miles on it so as far as Aeros go it should still be running strong.

 

It's not normal, but alot of times it's acceptable. There are rules for annual leakage of refrigerant. Like the display cases at grocery stores. EPA will let leakage slide unless more than a certain ammount per year, then the repair must be fixed. It's not regulated as much as it should be. Flourescent dye can be used. Some R-134a cans come with oil and dye.

 

all auto a/c systems develop leaks from vibration and aging

injectable leak detector, uv glasses and uv pen/light source are available separate from the sealer

see leak detection and repair section
i would not use the sealer, replace leaking part or repair
sealer is only a quick fix to get one home on trip...sealer is not the best goop to be putting into compressor, orifice or accumulator/filter

http://www.id-usa.com/how_to_videos.asp

 

I don't believe in sealers either one of the guys in the Explorer forums used so much of the radiator stop leak he actually made his problems worse. I can't imagine what it'll do in the higher pressure environment of the A/C system.

I saw the UV leak detector kit at Autozone is that can dye and refrigerant or just straight dye?

Thanks for the link mostly repitition but I always wondered what the pressure fittings on the R-12 systems looked like since the family cars are all 134a.

 

You can unscrew your pressure switch without losing any refrigerant. That fitting looks exactly like a R12 fitting, like a tire valve stem without the flexible part...

 

I would do two things, first, unplug and short the pressure switch on the accumulator. This will cause the compressor to run continuously. If the system now gets quite cold, your pressure switch is set for too high a pressure and shuting the compressor off prematurely. This would be fairly rare. The pressure switch is adjustable.

It is more likely that you have an undercharge. Consider adding half a can of refrigerant. This is more likely.

Gauges are great but these systems can be diagnosed on temperature and cycling characteristics fairly well.

This is more likely.

 

Well, since adding the R-134a improved performance, then you were low on refrigerant. I still recommend useing a guage. Working on the system without a guage, is like a dentist working on a cavity withou an x-ray. Sure he can find it and repair it without an x-ray, but he may miss things, or drill out more tooth than is needed. The temperature guage alone can do a fairly good job, in fact, I always use both, you need a thermometer to determine the temperature of the air entering the condensor. Once you know the oitside air temperature, you can put in in one of the inside vents, with the AC on max, full fan speed, and the windows rolled down. When your guages are connected, you watch the pressure of the low side and high side, and pressurize the high side towards the target pressure, based upon the outside temperature. Such a chart should be included with your gauge set. You can see at what pressure the compressor shuts off, and at what pressure it come back on. You can instantly see an changes in the performance in the system, even faster than you could feel or measure temperature changes at the vents. Based upon readings and the differences in the two guages, you can find pluged orfice tubes, and other problems in the system, which can be very helpful at troubleshooting, more so than other methods.

The reason I am such a strong supporter on useing gauges, is because we had our Aerostar serviced by a shop, that did not use a guage, and the system apparently got over pressureized 3 times (he added refrigerant according to the label on the blower motor cover). It destroyed just about every hose in the system ( some of which are very expensive), and I had to replace them again. Once I repaired it with the refrigerant I choose, it worked much better and has held pressure for over a year. Recently, my compressor stopped cycleing, so I need to test some things and find out why. My guess is the clutch, because there are no symptoms of internal compressor troubles, and the belt shows no glazeing. Shorting out the pressure switch yeilds no results. All fuses and other electrical seems to work correctly. I plan of troubleshooting in detail later this week, after I get my multimeter back. In any case, the use of the guage tells me, that the system has lost no measurable amount of refrigerant since I serviced the system last May.

 

Khanty is right, gauges are great but many people don't own them and these are simple systems so do your best without them and oftentimes one can effect a good repair.

Vehicle a/c systems normally leak several ounces of refrigerant past the compressor shaft seal per year. this is quite normal. even good hoses leak a tiny amount.

If my system required a can a year of refrigerant, I don't believe I would even try to seal it more tightly.

ken

 

I think I posted this to another thread already, but......

One way of properly charging a system without gauges, is the "thermometer method". Look at the temperature of the air exiting the vents. Add the refrigerant in 1 or 2 oz increments and keep a watch on the temp. When the temp bottoms out or slightly increases, you are at the right charge.

But, as mentioned previously, gauges are still the best way to go.....

 

Cookkd is correct. we are trying to achieve cooling, so how can the thermometer be wrong

Important to remember that the correct charge is the least refrigerant that causes accumulator to be cold in normal operation. Adding more decreases cooling and increases engine power drain.

Ken

 

vote on who tops off their ac system with combination refrigerant/oil or straight refrigerant

what brand and how much?

what type of oil and weight? PAG, ester, 100 or 46 weight?

who does full flush and vacuum evacuate with new accumulator and orifice after system leakout and leak repair?