Freon Pressures?

[scottyb]

For these who have done their own AC work, preferrably those in the humid south, please post your pressures and what you consider acceptable range.

I hooked up gauges the other day. The car still has r12, but the compressor has always been a bit noisy, and now when temps hit 90+, it can't keep up. It also seems to cycle a bit much on startup. The low side was bouncing off 20lbs as the compressor cycled, but after I let it run for a while, it settled just over 30, and high at ~225 at hot idle. Revving the motor will cause it to cycle sometimes.

 

[GNS-FLY]

cold air

As to help you on your cold air questions. First things first, you want to go by how many pounds of freon you have in the car. Your buick will need 3.25 pounds of R12. You want exactly that much for the system to blow as cold as possible. If you have less than that it will not blow as cold as it potential and the ac clutch will kick on alot with low freon. If you over charge the system the car will also not blow as cold as it should. It can even blow warm if there is to much in there. Before putting more freon in the system have the system checked for leaks with a dye or have the system hooked to a machine and sucked down to see it if it has any bad leaks or seals. You want to stay with r12 because it will blow colder than R134. At an idle R134 will warm up as to R12 will stay blowing cold at the stop light or and idle. R12 is very exspensive but it is worth it if you have no leaks. R134 is dirt cheap and works well also don't get me wrong. You can't tell the difference when going down the street between the two. You also want to make sure you put a couple of ounces of ac compresser oil in the system as well. The lack of oil in the system causes the ac compresser to groan or vibrate or make funny noise. But with my experence once they make noise it probally to late save the compressor. The compressor can still work perfect but it will just make noise and someday will lock up and break the belt. So maby you might consider a new or rebuilt one. Good luck and I you have any more question don't hesitate to ask.

Justin

 

[Scott Atk]

Going from memory the numbers you state sound pretty close. Were you checking it in the garage?? Remember your pressure is based on ambient. If you let the car run in the garage for more than a few minutes the temp. in the garage is gonna creep up and affect your numbers. I like to check the pressures outdoors, at a high idle and with a fan on the condenser. You'll need a PT chart (pressure/temperature) to know exactly what your looking for. But you're close.