Automotive Air Conditioning Information Forum (Archives)

SmokeandMirrorsTrick on Tue August 02, 2011 3:20 PM

Model: aurora
Engine Size: 4.0
Refrigerant Type: r134
Pressure Low: 45
Pressure High: 175-200
Country of Origin: United States

just had to replace the discharge line due to a pin hole leak in the rubber. pulled a vacuum for an hour. charged the system according to factory specs. (by weight) i've got 52 degree temps from the vent with max ac on. my low side is steady at 45psi with a 1 to 2 psi fluctuation. my high side fluctuates rapidly between 175-200psi. according to the digital gauge in the car it shows 95 degrees outside air temp. any ideas why the high side is so jumpy? any help would be much appreciated thanks.

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"he was hit by a Dodge, which I found funny and ironic."

GM Tech on Tue August 02, 2011 5:10 PM

probably coolant fan coming on from low to high and then high to low...

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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......

SmokeandMirrorsTrick on Tue August 02, 2011 5:22 PM

How would i correct that? I'm kinda new to the automotive ac scene and dont know much about it. I've got a basic understanding but some things are a little confusing. I work at a trans shop and have pretty much just performed r&r work. Our service plus guy quit so now i've been thrown into the fire and flames of all the ac work here. You'll probably be3 seeing more of me on here with more questions. I really hope to gain a pretty decent knowlage of automotive ac through work and this forum.

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"he was hit by a Dodge, which I found funny and ironic."

mk378 on Tue August 02, 2011 8:09 PM

If it's a model where the fans are designed to cycle, just accept that the high side is going to cycle along with them.

SmokeandMirrorsTrick on Tue August 02, 2011 8:29 PM

I think I may have over charged it a bit. The machine we have at work is new to me and I'm still getting aquainted with it. I think I used the kilograms dial instead of the pounds. I recovered the refrigerent and charged it again and it worked just fine.

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"he was hit by a Dodge, which I found funny and ironic."