[jntmjt1]

Hello,

When adding some R12 to my factory 1966 Bonneville's air conditioning system, what pressures (low and high side) should I be looking for for optimal performance?

Thanks,
John Thomas

[goodkarmech]

I see no one has replied, this is an older post, perhaps you have found your answer by now. A fully charged R12 system on your car should read low side between 20 and 30 psi and on high side 80 to 100 psi above the outside ambient air temperature, but it can be slightly lower. The better the airflow through the condenser, and the lower the ambient air temp. the lower the high side pressure will be. With a full system and no bubbles in the sight glass, I've seen 150 psi high pressure and cold air at the outlets, but it is usually closer to 200 psi. Hope this helps.
Al