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Are my r12 pressures right?

andy0221 on Thu May 29, 2014 11:05 PM User is offline

Year: 1990
Make: BMW
Model: 325i
Engine Size: 2.5
Refrigerant Type: R12
Ambient Temp: 90
Pressure Low: 38
Pressure High: 160
Country of Origin: United States

Am I over, under or just right?

90 degrees ambient

Idle 700rpm
38 L

2,000 rpm


Jag987 on Fri May 30, 2014 12:13 AM User is offline

Are the vents cold?

I bought a can of 134a at w**-mart that had a stop leak, oil, and dye in it. It also had a hose and a gauge, so now I'm an AC pro!

andy0221 on Fri May 30, 2014 10:03 AM User is offline

While driving the vents are 40. But the compressor cycles every 5 seconds. While at idle temp goes up to over 50. All fans are new and working correctly. It just seems to cycle a lot. It can't be good for the clutch. Thought my charge might be off.

mk378 on Fri May 30, 2014 10:26 AM User is offline

Cycling is usually controlled by an evaporator temperature sensor. Not much you can do about it, if it didn't cycle off it would freeze.

50 degree vents at idle in 90 F ambient is pretty good for most systems.

There should be a sight glass on the receiver, other than charging by weight that is the best way to judge the charge in an R-12 system. After the compressor has been running for several seconds, there should be a steady flow of liquid refrigerant with few or no bubbles. There will be bubbles during startup and after shutdown as the compressor cycles.

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