Why doesn't A/C Comp. cycle?
04-16-10, 08:20 PM
#16
I also have a 1991 and I was told by the Lexus tech it was supposed to cycle but 2 local A/C shops said they don't cycle I am still running R12 and I don't think my cycles I also saw a note about when the electrical fans should come on ,,mine don't come on utill I am in traffic on a hot day I also replaced my relays for the fans but I all I did was waste money the old ones are still good. Since you are in Texas it gets hot like So Cal in the desert here is a good bit of advice given by an old A/C guy go to the $2.00 self car wash lift the hood and wash out the A/C condensor top and bottom and then go to motor area and wash out the radiator DO NOT WASH THE ENGINE IT WILL CAUSE BIG PROBLEMS DO THIS EVERY YEAR..Your car will run cooler and the A/C will cool better good luck. Also always run the A/C in the winter months for about 10 minutes a week to keep the seals in the compressor soft.
04-16-10, 09:39 PM
#18
Hey Sam. Like I said in post #8 in this thread, the clutch should remain engaged as long as the AC button is on. This is normal. On my F-250 it will cycle on and off about every 10-15 seconds at idle. It's hard to tell over the noise of the engine at anything above idle as to what the compressor is doing. The cycling is normal on my truck and the compressor remaining engaged is operating as designed in the LS.
04-16-10, 10:02 PM
#19
I have another question. My ls is a 92 and it originally had R12. before I bought it it was converted to R134. I noticed that the ac made a noise that sounds a lot like a power steering low on fluid but not as loud. When they did the retrofit they put a sticker in the car telling what they did and what type of ac oil and how much ac oil they put in it. They put only 2.5 ounces of pag oil. From the research I did it should have between 6.5 to 8 ounces of oil so I added 4 ounces. The noise diminished but it not all the way gone. Is a little of this noise normal or did my compressor get damaged from running it on such low amounts of oil? The ac works fine just the noise.
04-18-10, 11:22 AM
#20
It will make a slight groaning noise during operation. Without hearing yours I can't say for sure but it sounds somewhat normal. If it's working fine I wouldn't worry so much about it. Depending on what parts were replaced during your retrofit and how much oil was removed will determine how much should be added. Off the top of my head I can't remember if the oil used in each system is compatible. If, for some reason, it is for your retrofit then they may have just replaced the dryer which would only required around 2.5 ouces of oil to replinish. I seem to remember that the oil's are not compatible, however I know there are retrofit kits out there that do not require flushing out all of the old oil.
04-18-10, 02:21 PM
#21
I hope that is not the case. I would think if I have that much oil in there it would not cool as well as it does. Can you hear the groaning noise inside the cabin with all the windows shut? By my ear it does seem excessive but I am comparing it to a toyota system that cycles (avalon, camry, 4runner)
04-19-10, 04:46 PM
#22
My 96 Land Cruiser definitely cycles. Interesting about the continuous operation. It makes sense.
So then onto my next issue. The suction lines are frost covered during operation. As soon as the line turns into that large "expansion" pipe next to the firewall at the evaporator it is all frost all the way to the compressor. The whole line in front of the condensor is white.
Replaced the specified oil amounts when I replaced the evap, expansion valve, and drier. System is ice cold. Filled to 2lbs of 134A. Pressure is 150psi on the high side and there are no bubbles in the sight glass.
I owned the car since 2004 and never noticed this. I wouldn't be surprised if my evaporator was leaking ever since I bought it. I have had a slow leak somewhere until I replaced everything.
So then onto my next issue. The suction lines are frost covered during operation. As soon as the line turns into that large "expansion" pipe next to the firewall at the evaporator it is all frost all the way to the compressor. The whole line in front of the condensor is white.
Replaced the specified oil amounts when I replaced the evap, expansion valve, and drier. System is ice cold. Filled to 2lbs of 134A. Pressure is 150psi on the high side and there are no bubbles in the sight glass.
I owned the car since 2004 and never noticed this. I wouldn't be surprised if my evaporator was leaking ever since I bought it. I have had a slow leak somewhere until I replaced everything.
04-19-10, 08:45 PM
#24
Probably 70 degrees ambient. According to the cheap fill can/gauge low side was somewhere around 30psi. I can hook up the gauges and get a true reading if needed.
If I press the A/C button to turn off the A/C then the pipes thaw out in about 5-10 seconds and drip everywhere.
If I press the A/C button to turn off the A/C then the pipes thaw out in about 5-10 seconds and drip everywhere.
04-19-10, 09:00 PM
#25
Your pressure is good high side should be 2.2 to 2.5 times ambient in degrees F
read this
Frost on the evaporator outlet is an indication of a problem with the thermostatic switch, suction throttling valve (STV) or pilot operated absolute valve (POA).Frost on a receiver-dryer or expansion valve usually means a blockage or restriction in the unit. Systems that have a thermostatic expansion valve (TXV) should have a warm receiver-dryer. On an orifice-tube system, the accumulator should be cool or cold. The line from the condenser to the expansion device should be very warm or hot. If it's not, there may be a high-side restriction.
http://findarticles.com/p/articles/m...g=content;col1
read this
Frost on the evaporator outlet is an indication of a problem with the thermostatic switch, suction throttling valve (STV) or pilot operated absolute valve (POA).Frost on a receiver-dryer or expansion valve usually means a blockage or restriction in the unit. Systems that have a thermostatic expansion valve (TXV) should have a warm receiver-dryer. On an orifice-tube system, the accumulator should be cool or cold. The line from the condenser to the expansion device should be very warm or hot. If it's not, there may be a high-side restriction.
http://findarticles.com/p/articles/m...g=content;col1
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