I replaced the AC compressor, dryer, and orifice tube on a 2002 eldorado. Of course I vacuumed the system and no leaks. Then charged with R134....

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Customer

I replaced the AC compressor, dryer, and orifice tube on a 2002 eldorado. Of course I vacuumed the system and no leaks. Then charged with R134. However the low side goes from 10 to 30 psi and high side 60-90 psi (81degrees). It is cycling between these values and the system will not take any more freon. The old compressor just quit working so no trash in the system (orifice tube clean). Oil replaced in compressor and dryer.

Last updated
Relly De Jesus
Cadillac Mechanic

Hello and welcome to ExpertHelp.com! My name is Relly De Jesus and I'm going to do everything in my power to answer your question to your full satisfaction!

Before we get started, I want to remind you ExpertHelp.com is an independent professional support company. We are not associated with CADILLAC nor are we paid to provide support on their behalf. However, we have helped hundreds of customers with similar questions and believe we can help you too. OK, let’s get started! :)

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Last updated
Relly De Jesus
Cadillac Mechanic

Hello Dave

How are you doing? May I ask if you replaced the expansion valve? I am suspecting that the expansion valve will require replacement as well. Here are some symptoms of a failing expansion valve

  • Car AC system isn't cooling enough or won't cool at all. ...
  • High side pressure is high. ...
  • Air coming from vents is frosty. ...
  • AC blows cold, then hot. ...
  • AC kicks on and then immediately kicks off. ...
  • Airflow drops dramatically from vents.

Expansion Valve

 

Hope this helps Dave and I'll be standing by for your response.

Thank you

Relly

Posted
Relly De Jesus
Cadillac Mechanic

Notes

- Called Dave and talked about the issue advised him to get back to the chat.

Posted
Customer

This system in the 2002 eldorado uses an orifice tube as an "expansion" valve. As stated it was replaced.

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Customer

It is 10 pm here so I will be going to bed. See you tomorrow. - dave

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Relly De Jesus
Cadillac Mechanic

Alright Dave will sort it out tomorrow... since you replaced the necessary parts needed there must be something else we can do. Catch you tomorrow. 

Thank you

Relly

Posted
Customer

I am back. Any more suggestions?

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Relly De Jesus
Cadillac Mechanic

Hello Dave

Good to hear back from you. I believe that you have done the proper procedure Dave but I'm suspecting this other 2 things. The a/c's high and low pressure sensor/switch. Either of the two can be faulty that's why this issue occur. 

If the AC low-pressure switch isn’t working properly, then it means that there is not enough oil in the system, and the compressor is working at low pressure, this leads to the AC system not being able enough to be able to cool the car properly. In such a case, you should replace the AC low-pressure system.

On the other hand, if it’s the high-pressure switch that is at fault, then it means that the compressor is working at high pressure, and it may lead to overheating of the system. In such a case, you may observe overheating and will be able to identify that the fault is in the high-pressure switch.

It's best to replace them both since it's a 2002 and it may haven't been replace eversince. Hope this helps.

Thank you

Relly

 

Posted
Relly De Jesus
Cadillac Mechanic

Hello Dave

Good to hear back from you. I believe that you have done the proper procedure Dave but I'm suspecting this other 2 things. The a/c's high and low pressure sensor/switch. Either of the two can be faulty that's why this issue occur. 

If the AC low-pressure switch isn’t working properly, then it means that there is not enough oil in the system, and the compressor is working at low pressure, this leads to the AC system not being able enough to be able to cool the car properly. In such a case, you should replace the AC low-pressure system.

On the other hand, if it’s the high-pressure switch that is at fault, then it means that the compressor is working at high pressure, and it may lead to overheating of the system. In such a case, you may observe overheating and will be able to identify that the fault is in the high-pressure switch.

It's best to replace them both since it's a 2002 and it may haven't been replace eversince. Hope this helps.

Thank you

Relly

Posted
Customer

I suspected the low pressure switch very early on, so I bypassed it but it didn't cure the problem. Since the compressor is working at a very low pressure the hi pressure switch is not open so it is OK. The system is not overheating - all pipes are cool to warm.

I believe the low TEMPERATURE  sensor may be the problem. It monitors the freon temp and if it gets to cold it will cycle the compressor. So, I have ordered a new one. Will let you know how that works out. I measured the voltage going to that sensor and it was 4.96 and the other wire was grounded so HVAC module is OK. All for now.

Posted
Relly De Jesus
Cadillac Mechanic

Hello Dave

Hope everything is well. Any update on our ac issue? I'll be standing by for your response

Thank you

Relly

Posted
Customer

I should receive the ac temperature sensor tomorrow. I will let you know if that fixes it. But in the mean time maybe you could help by seeing the next paragraph.

Are you familiar with the 2002 Eldorado AC system? If so, maybe you can explain how the various components work. I seems to be complex. I notice it has many more components then most systems. That may help me figure out how to approach fixing it. I am familiar with most systems but this one is not easy. I guess Cadillac likes to do things different. 

One other thing - you mentioned replacing the low and high pressure switches. Have you experienced faults with these switches that could cause the problem I am having?

Hope all is well with you...

 

 

 

 

Posted
Relly De Jesus
Cadillac Mechanic

Hello Dave

Good to hear back from you. Not much CADILLAC coming in and if there is it's just usually ac cleaning. We have an issue once and replacing the switches does the fix. And yes I can agree with you that it's complex

Relly

Posted
Customer

OK, will see it the sensor fixes it. If not, I will replace the low and high pressure switches. Should know tomorrow if the sensor fixes it.

All for tonight..

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Relly De Jesus
Cadillac Mechanic

Got it Dave... you have a good one! Hoping for the best. Thank you!

Posted
Relly De Jesus
Cadillac Mechanic

Hello Dave

How are you doing? Any update

Relly

Posted
Customer

The low temperature sensor did not fix the problem. So, I will try replacing the low and high pressure sensors. Will let you know if that fixes it. If not,,I am out of ideas. So any thoughts you may have? Pressure sensors will be here after 4 o'clock our time so won't get them installed until Saturday. All for now..

Posted
Relly De Jesus
Cadillac Mechanic

Got that Dave... yes please do replace them and I'll go dig deeply on what can be the other causes since the majority have been replaced. Have a good one!

Posted
Relly De Jesus
Cadillac Mechanic

 Hello Dave

Hope everything is well. I am thinking if of soft resetting the ECU to clear the system. Try removing the negative battery connector and let it sit for 10 minutes or so before reconnecting it. The system will relearn and can get the ac back to it's normal operating state. Will let you know if anything else I can add. I'll be standing by for your response. Have a good one!

Thank you

Relly

Posted
Customer

I had some family matters to take care of so didn't get the switches installed. Will get back with you Monday.  All for now.

Posted
Customer

I had a little time this morning so installed the pressure swithes and ran the AC system. Disconnected battery for 15 minutes so all codes erased. Still no change. So,,,I decided to remove the compressor relay and jump start the compressor (which I don't like to do). To my surprise the low side went to a vacuum ! (-10) and the high side went to 75 psi. I also did some research and found when the "low refrigeratant" displays it does so because the low TEMPERATURE sensor monitors the AC charge through the sensor. If the charge is too low the freon boils immediaately after passing thru the orifice tube. This creates a large rapid change in the AC freon low temp sensor and triggers  the "low refrigerant" message. and turns off the compressor. I always thought the low PRESSURE switch is what turned off the compressor. But I guess it functions when there is a quick loss of freon..    

I replaced the low temperature sensor several days ago as noted below. Also since I had to discharge the system to do so,,I doubled checked the orifice tube (that was also new) and it was the correct yellow color and was in place. So,,now I am thinking the NEW compressor is possibly bad or the HVAC processor is defective. I would assume if the HVAC processor was bad that would set a code..

If you know of anyone that has worked on the 2002 Elorado AC and could possibly add anything to this problem I would appreciate. This is a very complex system. All the AC systems I have worked on were straight forward (older cars)..

Posted
Relly De Jesus
Cadillac Mechanic

Hi Dave!

Good to hear back from you. Yes if the HVAC processor is bad it will trigger a code. I am thinking about that new compressor too was a defect as well because there was an instance that I installed a new compressor and it turns out that it's faulty. Can you check if the condenser fan is turning on once you turn on the AC? I'll be standing by for your response.

Thank you

Relly

Posted
Customer

The eldorado is unique as it uses a high temperature sensor in the liquid line to notify the PCM to turn on the fans whenever the liquid freon becomes too hot. I did check this sensor by unplugging it which turned on the fans. Most cars, as you know, turn on the fans as soon as you turn on the AC and are under 25 mph. I have 7 other cars (older cars) of which 4 have AC and they all turn on the fan as soon as the AC is turned on.

The service manual states this is how this car turns on the fan, ie, thru the high temperature sensor. I have a couple more things to check, but feel the compressor is bad. Can't do it today as I am watching my granddaughter. All for now.

Posted
Relly De Jesus
Cadillac Mechanic

Yes please Dave. If you only have an old compatible compressor to test it and just to check if the new one is faulty. I'll be standing by Dave. Have a good one!

Posted
Customer

I don't have an old one to test it. But I am going to get a new one and if that fixes it I will return the one I have now under warranty. Shouldn't be a problem as I have receipts for dryer and orifice tube replacement. Should only take a couple days to get it here (Autozone).

I wonder if the evaporator or condensor could be partially plugged? Since I will take the system down I may blow filtered air thru them. Sound reasonable?

Posted
Relly De Jesus
Cadillac Mechanic

Yes indeed Dave. If only we have an old compatible compressor just to check if the new one is faulty. I'll be standing by for your response. You have a good one!

Posted
Relly De Jesus
Cadillac Mechanic

Hello Dave

Please do check the condenser as well for it may be clogged since everything is pulled down before installing the replaced compressor. I know that you know this but please don't forget to put the ac switch on the full level while filling up the freon. It will be best that someone is pressing the gas pedal to atleast 2000 rpm while filling the freon. I believe that you'll be good after this procedure. I'll be standing by for your response.

Thank you

Relly

Posted
Relly De Jesus
Cadillac Mechanic

Good day Dave

How are you doing? Any update on the issue? I'll be standing by for your response.

Thank you

Relly

Posted
Customer

The new compressor fixed the problem!

Posted
Relly De Jesus
Cadillac Mechanic

Dear Dave, It was a pleasure helping you with your Cadillac issue today and glad that it's back to it's normal operating state.


Issue identified : ac problem


Solution Implemented : Called and chat with the customer and discuss about the possible solution. 

Accepted Answer


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