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Low and High pressure recommendattions

abw121 on Thu July 25, 2013 12:55 PM User is offlineView users profile

Year: 2006
Make: Jeep
Model: Liberty
Engine Size: 3.7
Refrigerant Type: R134a
Ambient Temp: 70
Country of Origin: United States

Second question for forum.

My 2006 Jeep liberty A/C system was rebuilt with new comprssor, condensor, accumulator and Liquid Line.
Flushed out the Evaporator and lines. Installed 8oz of PAG 46 oil thru system.

The entire system was vaccumed down to 30 hg for 1 hour which then sat for over 8 hours holding vacuum. GOOD TO GO.

What are the OEM recommended Low and High pressure limits for ambient temps of 70, 80 and 90 degrees???



iceman2555 on Thu July 25, 2013 3:52 PM User is offlineView users profile

The system should be recharged to OE specifications...utilizing the correct equipment...not cans....and then the pressures become a valid representation of system operation. If you are seeking a 'assumed acceptable' pressure for determining recharge rate....look elsewhere. Pressures should never be used as a method to determine charge rates.
A true operational pressure range for a given temp can be obtained from on line data services. Asking a tech for this info will result in various responses....since most operate within a given pressure range that has been accepted over years of experience. This is not always wrong....but may not be what you are seeking. Put 100 techs in the same room....ask this question....and one would probably receive 100 different responses.....obtain your info from an on line data source.....perform the recommended test to determine system operations and efficiency.
Key factor...the system must be totally and properly recharged...first...first....always...first.

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

TRB on Thu July 25, 2013 7:02 PM User is offlineView users profile

Ice that is a very informative response. It only say this becasue I agree with you on the 100 mechanics in a room suggestion.


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

bigkev on Fri July 26, 2013 2:28 AM User is offline

What is incorrect about cans if you purge the line?

GM Tech on Fri July 26, 2013 7:22 AM User is offline


The number one A/C diagnostic tool there is- is to know how much refrigerant is in the system- this can only be done by recovering and weighing the refrigerant!!
Just a thought.... 65% of A/C failures in my 3200 car diagnostic database (GM vehicles) are due to loss of refrigerant due to a leak......

bigkev on Fri July 26, 2013 6:09 PM User is offline

I would think that the scale inaccuracies would be just as bad as loosing a little of each can. A scale with +/-.5% is considered very accurate, so isn't that a little off also? Refusing to use cans just seems like one of many myths that the pro's develop. Do you guys really think an ounce makes a huge difference? I remember being told that non-barrier hoses would not work with 134, I guess on paper some things make sense, in the real world not so much. What if someone vacuumed the line before puncturing the can instead of purging it? Maybe more accurate as I would guess that the factory that fills the cans has scales that are more accurate than a technicians.

wptski on Fri July 26, 2013 6:41 PM User is offline

I often wonder about things like this where someone states how important it is. I then wonder how is it performed on a moving assembly line. The same goes for things like brake bleeding too.

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