Posted by Charlie (IP: 131.204.83.107) on May 03, 2000 at 14:58:46:
In Reply to: Re: Still running R-12? posted by DJ on May 03, 2000 at 14:18:09:
When the bubbles stop, stop charging & it'll be as close as necessary. Any more will bring your high side up too high. The high side depends on temp & also fan speed. If you go down the road at 55 mph the high side is very different than ad idle, but it doesn't make a huge difference. I've done lots of ac work and am still doing it and if a car has a sight glass we don't even hook up the high side unless for diagnostic purposes. It just doesn't affect the cooling much. -CP
: YES R-12
: The sight glass is good just so far. You are right, getting the low side to cycle in the
: 20-40 psi range is the target. The low side is generally not
: affected too much by outside air temp, but the high side, depending
: on the system, can range from 170 to 220-240 and is greatly affected
: by the outside air temp. I have always kept an eye on the high side pressure
: when recharging but today I can't find my temp chart for this car.
: : It makes a difference if you are running R134a or R12. Generally with R12 you want the compressor to bring the low side down to 30-40 psi, while the high side shouldn't go above 250. The low side is what gives you cold. That car should have a sight glass though, doesn't it? Always go by the sight glass if you have one. -CP
: :
: : : Does anybody have the specs for high and low side pressure readings
: : : at various ambient air temperatures for a 77 Mav ?