suction-side psi on w124 r-12 system

[GregS]

I am looking for a tech out there who knows what the ideal psi should be on the suction side of my a/c system. Its a 1990 300CE with r-12.

Thanks,

GregS
'84 300D, 174k
'90 300CE, 164k

[stevebfl]

The presuure equals the temp and a chart will give it and every R12 system would be the same in this reguard.

Ideal would be the pressure equal to 32.something degrees F. Or just above the freezing point at the atmospheric pressure one exists in.

The pressure that would give that temp is somewhere around 27psi. The system will cycle before it hits that pressure, unless...... and thats the point. It gets complicated from there.