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Help w/gage readings..what can you tell me?

paulrv6 on Tue July 15, 2008 10:26 AM User is offline

Year: 1996
Make: Olds
Model: Aurora
Engine Size: 4.0L
Refrigerant Type: 134
Ambient Temp: 70
Country of Origin: United States

My AC seems to work intermittently, I hooked my gage to LP side and here is what I found:
Before starting car - 105 psi
Started car and turned AC on high - 40 psi
Turned AC off (car still running) - 65 psi
This is with an ambient temp of 70 deg F.

I can here the clutch engaging so the switch appears to be working.

I don't have a HP gage otherwise I would have given you those. Can you diagnose anything given these readings? Thank you for any help
you can offer.

paul

mk378 on Tue July 15, 2008 10:30 AM User is offline

You can't tell much with a single gauge. Both pressures are needed.

But, intermittent operation is usually not refrigerant related. A common problem is having the clutch gap too wide. Wait until the system is NOT cooling then see if the clutch is still engaged.

JJM on Wed July 16, 2008 3:06 AM User is offline

Just like a doctor can't diagnose your heart and blood pressure with only the diastolic pressure, we can't diagnose your A/C system with only the low side pressure.

Joe

When considering your next auto A/C purchase, please consider the site that supports you: www.ACKits.com




paulrv6 on Thu July 24, 2008 9:29 PM User is offline

Ok guys I got both high and low readings, just like the heart doctor. Ambient temp is 66 F. High side is 160 psi and Low side is 40 psi. It was cycling with the AC on high but it was working. During the cycling, Low side would go to 55 psi with high side going to 125 and then 60 psi and 110 psi on the high side. What can you tell me about these numbers?
If you need more data to diagnose please let me know, I will get it. Thanks everyone.

paul

iceman2555 on Thu July 24, 2008 11:02 PM User is offlineView users profile

If you would like pressures to be really indicative of your systems performance....have the system recovered...evac'd....and recharged to OE specs. Once the vehicle is completely and properly recharged...pressures become truly indicative of system performance.
The first and most important variable to remove from a system diagnosis is knowing how much refrigerant is in the system.

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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.
Thomas Jefferson

paulrv6 on Fri July 25, 2008 8:20 AM User is offline

Yea but I know there is something wrong, so can't these numbers tell if if needs refrigerant or if is not pumping before I go spend a fortune to have them tell me it needs repaired? Isn't this the whole idea of getting gage readings?
Someone earlier said to get both high press and low press readings which I have done. Am I low on freon, is the compressor not working properly, is the system plugged? Any ideas?
Thanks

paul

Keepin_it_Cool on Fri July 25, 2008 11:21 AM User is offline

You need to make note of what your LS pressure is when the system cycles (your compressor cuts out.) This should cycle between 28 and 30 psi on your low-side. If it's cycling above 32 psi then your low pressure cut out switch is bad. Replace the switch and if rapid cycling occurs you are low on refrigerant.

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Keepin it Cool!

iceman2555 on Fri July 25, 2008 8:36 PM User is offlineView users profile

Well...suppose we could all sit here on our cans and 'guess' about what is happening within your system...or perhaps....a direct and proper approach to a complete diagnosis of this problem could be arrived.....get it recovered...evac'd....and recharged to OE specs.....then the guessin' is all gone and a proper and complete diagnosis can occur.....!

-------------------------
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.
Thomas Jefferson

Chick on Fri July 25, 2008 9:22 PM User is offlineView users profile

Also, the Aurora, like the cads, cycle off the refrigerant temp thermistors, not a cycling switch.. I also agree with the recover (weigh if possible) and recharge into a good vacuum before any proper diagnosis can be done, especially with the Aurora and Cads..Just my opinion...

Oh, just to add, once the system is empty, remove and inspect the O tube. It's located between both service ports. (right in the middle of them). Those cars were known for reed valve failure, and you may see it on the O tube. High low side pressures can point to this, but as stated, recharge to OEM specs...Hope this helps.


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Chick
Email: Chick

---------------------------------------------

Freedoms just another word for nothing left to lose

Edited: Fri July 25, 2008 at 9:25 PM by Chick

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