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Anonymous Posted on May 16, 2017

Low/high side A/C compression reads the same

No A/C, was professionally diagnosed as a bad compressor. I replaced the compressor, accumulator, and both front and rear expansion valves (front/rear air). Pumped down and held vacuum. When I started to install freon, both high and low sides together come up and peaked at about 80 PSI. Can't even get a whole can of freon in. If I rev the engine, the low side will drop to about 70 and the high side will go up to about 90. At engine idle both will immediately equalize back to about 80 PSI. I welcome any suggestions.

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D Aubrey

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  • Pontiac Master 1,136 Answers
  • Posted on May 28, 2017
D Aubrey
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Why was the compressor diagnosed bad?Did it send anything into the system that may have blocked a line?Did you flush the complete system?
I would have started the compressor by jumping the low side switch to make sure it could pull a good vacuum before adding any 134a.
You may have a blocked system with debris/grindings from the old compressor?
The replacement expansion tubes may be blocked now,were the old ones clean?
Make sure you have good air flow through the condenser when refilling the system.
Does the new compressor sound like it's working correctly?
I still want to see it pull a good vacuum first.

2 Related Answers

Anonymous

  • 630 Answers
  • Posted on Jul 21, 2010

SOURCE: AC problem with 2001 Montana passenger van

Did you replace the expansion valve?
Also try adding just a little more freon and see if that makes a difference....is there a sight glass you can view with the system activated to be sure you have it completely air free?

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NomadTrucker

Nomad

  • 166 Answers
  • Posted on Jun 30, 2011

SOURCE: i have installed a new accumulator, evaporator,

Is the pressure detection switch engaged? It detects pressure in the cooling system. This switch shuts down the clutch to prevent the compressor to run when there's a leak.

Sometimes there's a looking glass on the expansion bottle showing tiny bubles. A large blob of air indicates too much air in the system. Pressure might not be enough to engage the switch when there's too much air left.

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Where exactly is the high pressure switch located...my A/C is blowing warm air...I jumped the low pressure switch on the accumulator and the compressor cuts out at 40...on the gauges...

If the high side switch was bad, the compressor would come on at all. The low side is only on with the compressor running. You need a set( high and low) gauges on it to determine the problem.
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Replaced all A/C major components (compressor, filter-drier accumulator, and orifice tube) except condenser due to a seized compressor and failed clutch bearing. Flushed system and appeared to have no...

It sounds like you've done just about everything except to check if there is a bad or intermittent wire causing this or perhaps your low-pressure safety cutout switch is possible going bad causing the compressor to kick on and off?
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Will only blow hot air ac compressor working and i replaced he blend door actuator still not working

Two possiblities. The freon charge levels will need to known on both the low and high side. with a good unit running the low side with the engine reved up should not be less than 25 PSI and the high side can be 175 or as high as 225-250. if not your looking for the problem, if the low is too high and the high is'nt very high the compressor likl;y to be bad if the low is too low and the high is too high the comdenser is clogged or the air flow might not good though as the fan or dirt not going though. the orfice tube could be stopped up but if it is the compresser is failing. and parts are flying though the system. high on the low side the system could be containated with moisture ( too much in the system ) Evascate and recharge may get ti working playing carefull attention to the charge rate astoo much freaon can do the same thing.
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AC problem with 2001 Montana passenger van

Did you replace the expansion valve?
Also try adding just a little more freon and see if that makes a difference....is there a sight glass you can view with the system activated to be sure you have it completely air free?
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Low pressure side of air conditioner reading very high pressure. Compressor may not be engaging??

very high pressure suction will cut by high pressure sensor to command compressor on/off, release refrigerant, check condenser clogging, filter drier expansion valve, or accumulator and orrifice filter and tube
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My a.c is not cooling i put freon in and my compressor will only come on every now an then i replaced the switch in the dash but still did not help i did use a jumper wire to my compressor and it...

You may not have enough R134a in the system, or you have over charged the system and your high pressure switch is turning your compressor off when the pressure get's to high.
You really need a A/C gauge set to see of your system is over or under charge. If it's under charge, that's good. A over charged system will cause your a costly repair of replacing a $300.00 rebuilt compressor plus the vacuuming out the system and replacing the accumulator which may have parts from the compressor (bearing).
Normal readings on high and low side with AC OFF (static pressure) – Depends on outside temperature, but normally is between 80-105 PSI
Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s – Ranges from 25-35 PSI – Note that on many Chrysler products a normal reading on the low side may be 15-25 PSI
Normal high side reading ranges from 200-350 PSI
Could be overcharged, not enough air going across condenser fins, compressor not pumping sufficiently… BOTH gauge readings are really needed to get a better idea.
Don’t assume that if adding little Freon is good that adding a lot is better! Overcharging just a little can decrease the performance of the system and possibly damage the compressor, assuming the blower speed is on high, AC is set on maximum and engine is around 2,000 RPM’s

1. Check the high and low gauge readings with the AC on & set on MAX/Recirculate, middle vents with the engine at 2,000 RPM’s, blower speed on high.
2. Check the vent temperatures with a thermometer from the middle vents, far right & far left vents?
3. What is the outside temperature at the time the readings were taken? 4. Check to see if the condenser fan blowing strong?
5. Notice if compressor clutch is cylcling excessively.



Thank you for using fixya and good luck


1helpful
2answers

No ac

sounds like it could be one of many things, a plugged condenser or evaporator (inside or outside), a plugged orifice tube or a faulty compressor. If you don't can't turn the vapour refrigerant into liquid, it doesn't cool. Also, if you can't turn the liquid into a vapour, there is no flow of refrigerant, and therefore, still no cooling. It is common for dirt to accumulate in the evaporator core or the condenser and not allow it to cool.
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I have replaced my ac compressor w/ a new one and two reconditioned compressors and they have all gone bad within a month. 1996 izuzu rodeo

When the A/C compressor was replaced and recharged, was the system vacuumed and the accumulator and orifice tube (expansion valve) replaced too. Also was the right amount R134a in the system to run properly??
To diagnose problems, an A/C manifold gauge set is needed to read high and low side pressure readings. Avoid adding refrigerant with a simple charging kit like the ones sold at parts stores. Don’t add any stop leak, this can cause problems in the compressor, expansion valve or condenser.

Keep in mind that using an A/C gauge set and seeing BOTH high and low side readings can help in diagnosing the problem when you know what to look for. First, on a 134A system the high and low side service ports are different sizes. AC gauge sets have color coded hoses, the blue color coded hose has a connection that fits on the low side service port and the red hose has a connection that will only fit onto the high side. The yellow hose won’t hook up to anything if just checking the readings; it can be used to connect to a vacuum pump or attached to a refrigerant can or tank.

Normal readings on high and low side with AC OFF (static pressure) - Depends on outside temperature, but normally is between 80-105 PSI Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s - Ranges from 25-35 PSI - Note that on many Chrysler products a normal reading on the low side may be 15-25 PSI Normal high side reading ranges from 200-350 PSI Don’t assume that if adding little Freon is good that adding a lot is better!  Overcharging just a little can decrease the performance of the system and possibly damage the compressor.

With the AC on the coldest setting, use a thermometer in a middle vent. Normal vent temperature readings will vary depending on the (ambient) outside temp. The vent temperature should range from around 42-55 degrees in my experience. If normal gauge readings are obtained and the vent air is cold - STOP don’t overcharge the system. The only proper way to remove refrigerant is with a AC recovery machine so if this is being done at home I can’t emphasize enough not to over charge the system. And actually the best way to insure the proper charge is in a system, is to use an AC machine to recover the R134a and then evacuate and recharge the system with the correct amount. Most cars have the specified amount on a decal under the hood.

Both low and high side readings are lower than normal, this indicates a cars AC system is low on refrigerant and is under-charged. If both low and high side readings are too high, this indicates an overcharged system - too much refrigerant. This also can indicate that the condenser fan is not working, is too slow or the car is overheating and heat is transferring from the radiator to the condenser. 

When the low side goes so low that it’s reading shows it is in a vacuum, the most likely cause is a bad expansion valve or blocked orifice tube. Another possibility is a restricted condenser. Blocked condensers are not as common as they used to be but if a compressor fails and comes apart inside the remnants can end up in the condenser causing it to restrict the flow of refrigerant.

When the compressor clutch is definitely engaged and the low side is high and the high side is low, the most likely cause is that the compressor is failing - it is not pumping sufficiently. Rarely an AC clutch could be slipping but usually this will be accompanied with a squeal or chirp.

I hope this will help you understand why the comprssor failed, Keep me posted, be glad to help you get your A/C running 100% again. 
1helpful
1answer

Ac wont get cold after adding refrigerant

To diagnose problems, an A/C manifold gauge set is needed to read high and low side pressure readings. Avoid adding refrigerant with a simple charging kit like the ones sold at parts stores. Don’t add any stop leak, this can cause problems in the compressor, expansion valve or condenser.
Keep in mind that using an A/C gauge set and seeing BOTH high and low side readings can help in diagnosing the problem when you know what to look for. First, on a 134A system the high and low side service ports are different sizes. AC gauge sets have color coded hoses, the blue color coded hose has a connection that fits on the low side service port and the red hose has a connection that will only fit onto the high side. The yellow hose won’t hook up to anything if just checking the readings; it can be used to connect to a vacuum pump or attached to a refrigerant can or tank.

Normal readings on high and low side with AC OFF (static pressure) - Depends on outside temperature, but normally is between 80-105 PSI Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s - Ranges from 25-35 PSI - Note that on many Chrysler products a normal reading on the low side may be 15-25 PSI Normal high side reading ranges from 200-350 PSI.
Don’t assume that if adding little Freon is good that adding a lot is better!  Overcharging just a little can decrease the performance of the system and possibly damage the compressor.

Both low and high side readings are lower than normal, this indicates a cars AC system is low on refrigerant and is under-charged. If both low and high side readings are too high, this indicates an overcharged system - too much refrigerant. This also can indicate that the condenser fan is not working, is too slow or the car is overheating and heat is transferring from the radiator to the condenser.

When the low side goes so low that it’s reading shows it is in a vacuum, the most likely cause is a bad expansion valve or blocked orifice tube. Another possibility is a restricted condenser. Blocked condensers are not as common as they used to be but if a compressor fails and comes apart inside the remnants can end up in the condenser causing it to restrict the flow of refrigerant. 

When the compressor clutch is definitely engaged and the low side is high and the high side is low, the most likely cause is that the compressor is failing - it is not pumping sufficiently. Rarely an AC clutch could be slipping but usually this will be accompanied with a squeal or chirp.

Hope this helps. If the compressor did come on and pulled the R134a in to the system, you may still be low or you may be over charged. With out any pressure readings it's had for me to say what is the problem. You could also have a bad orifice tube ( expansion valve) Good luck and hope this helps. 
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95 Deville - Low Refridgerant/AC Comp. off

To diagnose problems, an A/C manifold gauge set is needed to read high and low side pressure readings. Avoid adding refrigerant with a simple charging kit like the ones sold at parts stores. Don’t add any stop leak, this can cause problems in the compressor, expansion valve or condenser.
Keep in mind that using an A/C gauge set and seeing BOTH high and low side readings can help in diagnosing the problem when you know what to look for. First, on a 134A system the high and low side service ports are different sizes. AC gauge sets have color coded hoses, the blue color coded hose has a connection that fits on the low side service port and the red hose has a connection that will only fit onto the high side. The yellow hose won’t hook up to anything if just checking the readings; it can be used to connect to a vacuum pump or attached to a refrigerant can or tank.

Normal readings on high and low side with AC OFF (static pressure) - Depends on outside temperature, but normally is between 80-105 PSI
Normal low side reading with AC on high speed and MAX & engine at 800-1000 RPM’s - Ranges from 25-35 PSI - Note that on many Chrysler products a normal reading on the low side may be 15-25 PSI
Normal high side reading ranges from 200-350 PSI

Don’t assume that if adding little Freon is good that adding a lot is better!  Overcharging just a little can decrease the performance of the system and possibly damage the compressor.

Both low and high side readings are lower than normal, this indicates a cars AC system is low on refrigerant and is under-charged.
If both low and high side readings are too high, this indicates an overcharged system - too much refrigerant. This also can indicate that the condenser fan is not working, is too slow or the car is overheating and heat is transferring from the radiator to the condenser.

Good luck and hope this helps, keep me posted be glad to answer any question you may have. And yes the A/C system on your car uses R143a and there is a A/C pressure switch along the low pressure line or on the accumulator, it looks like a oil pressure sensor with a two wire lead cliped on it. 
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