2 days ago it was 100F ambient full sun and my AC was dismal, barely kept me from sweating.

I just added more 134A (what's left about 1/3 of a can) and got the vent temp down to 7C (44.6F) with ambient of 90F with the sun down.

Should I get another can and add more to get vent temp lower? How do I tell when to stop? The low side reading stayed at 40 psi after the added refrigerant. I don't have high side pressure readings since the coupler won't mate.

__________________
85 300D turbo pristine w 157k when purchased 167,870 July 2025
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked