Situation: Charged 4 Pounds: R12 Low Side: 50-55 High Side 260-280 Outside Air ~90* GOOD Condenser Airflow. 57* At Center Vent Clear Sight Glass Replaced expansion valve, condenser, compressor, Suction hose, and POA valve in the past with NO CHANGE in cooling. I initially charged with 3.5 Pounds and Cooling was equally at bad. Unplug blower motor and low side goes to about 40-45. Do I need to SCRAP this Buick because the A/C refuses to cool? I am sick and tired of this car's A/C it has never worked well since I got it 6.5 YEARS ago. :af:
Is the hot water valve working correctly and cutting off the hot water to the heater core? There is a difference in the big car and skylark heater hot water valves. What kind of air flow are you getting from the blower fan? Have you got the radiator sealed against the core support so that the air pulls through the condenser? Are the lines freezing up? How long did you hold it on vacuum before charging? You should be able to get around 42*- 45* vent temp if the car is not heat soaked. Was the POA valve set for the R134 or the R12? They can be adjusted. Nelson
Suction pressure should be 38- 42 using R12. Your overcharged. To much is just as bad as not enough when it comes to freon. http://www.tecumseh.com/en/canada/library/~/media/North%20America/Files/Marketing%20Brochure/North%20America%20Library/Temperature%20Pressure%20Chart.ashx
Airflow is not the issue. A/c behaves the same parked versus 70 down the interstate. I held a vacuum for 20 minutes. Steady as a rock. No lines are freezing. Hot water valve is shut off. ---------- Post added at 08:36 AM ---------- Previous post was at 08:33 AM ---------- Yes I know my low side is high. And NO I am not overcharged. With 3.5 pounds my low side and high side was still high and the car did not cool.
Did you adjust the poa valve at all b4? just trying to trouble shoot over the Web.what brand of freon did you use? Freeze 12 maybe? I ask BC diff refrigerants have diff saturation points so you wouldn't need as much or maybe need more. Good deal on the vacuum though.
I played with the little adjustment screw on the outlet side of the Poa valve years ago. Adjusting it never changed anything though. I did not use Freeze 12. It was Igloo or something like that but it was plain R12.
Ok cool, maybe this is easy. Try adjusting the poa valve. Question on your (txv expansion valve) is the cap tube that reads the temp from the top evap coil suction line insulated? Could very well BA bad txv
I think you are on to something with the POA valve. It is frustrating because it seems like my original POA and replacement have performed poorly. I will contact Classic Auto Air tomorrow about getting a properly calibrated POA for R12. My sensing bulb does have the monkey poop wrapped around it. Now I need to buy some recovery equipment off Craigslist. $$$
Ok start with the sensing bulb... Get that thing insulated good. The freon inside it is (what makes the txv meter the refrigerant) then check the charge again. has to b insulated and positioned about 2 or 10 o'clock on the suction line.
You didn't mention the evaporator. When is the last time your evaporator box has been opened? Perhaps the evaporator fins are plugged? This is what mine looked like when I opened the box. Not to mention all the leaves and such.
