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what are recommended AC pressure for 07 PT Cruiser?

dwjmd79 on Fri April 01, 2011 3:04 AM User is offline

Year: 2007
Make: Chrysler
Model: PT Cruiser
Engine Size: 2.4
Refrigerant Type: R-134a
Ambient Temp: 70
Pressure Low: 45
Pressure High: 330
Country of Origin: United States

my mechanic has tweaked my AC pressure to be 45 lo side and 380 high side. he says that gives optimum cooling. the local Chrysler dealer says the factory spec for the AC pressure should be 34-38 lo side and 270-330 high side.

is it possible that the higher pressures can cause a liquid pressure line to leak and the compressor pop off valve to blow or fail?

also on a cold start the compressor blows a cloud of smoke which i suspect is freon and the compressor makes a rough chatter like its trying to compress air or failing to compress liquid and then the puff of smoke comes out the pop off valve. what causes the compressor to chatter on a cold start and the pop off valve to release freon and pressure when the car is starting cold?

my mechanic is convinced that the pop of valve is defective and that it just failed, and that it has nothing to do with the fact that he just serviced the AC and replaced a liquid pressure line and filled the AC system with higher thatn normal pressures.

what should the pressures be for an ambient temp of 70F and if the engine is cold?

Chick on Fri April 01, 2011 6:39 AM User is offlineView users profile

Could be the pop off valve is they blow they don't always re-seat themselves..But, bring it to someone who knows what they are doing, just adding refrigerant may damage your system...Have it recovered (weigh it if possible) then after changing your pop off valve, have the system charged properly by weight into a deep vacuum, make sure your condenser fans are working properly and the condenser is clean of dirt and bugs....Not all mechanics are good AC techs....

Email: Chick


Freedoms just another word for nothing left to lose

mk378 on Fri April 01, 2011 6:56 AM User is offline

Seems to be severely overcharged and/or contaminated with air.

Empty systems after line replacement or other opening of the system must always be evacuated to remove air, then charged by weight to the manufacturer's spec. Once you know the charge amount is proper, then you start comparing the pressure to spec to see if there is another problem.

In addition to what Chick said, ask if any oil, sealer, etc. has been added-- too much oil will cause similar symptoms and other "magic in a can" is no good at all.

JACK ADAMS on Mon April 04, 2011 7:32 PM User is offline

The proper charge amount should be 1.125lbs of 134a refrigerant. Also the tag under the hood should say what the charge amount should be as well. The Hi-pressure should open between 450-490psi and reset at 270-330 psi. Hope this helps and good luck...

chris142 on Sun April 10, 2011 10:30 PM User is offline

I have 2 AC books and both list 1lb 8oz lbs for the PT. But every PT I have worked on had a sticker that said 1lb 2oz. Maybe he has the same book with the wrong spec?

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