924s A/C ports

[Porsche1987s]

I have a 1987 Porsche 924s, and I am trying to identify the low pressure port to my AC, to add Freon.

Is it picture A by the firewall
.

Or picture B by the front right air filter,


Thanks
Kevin

[Pauld_94S2]

R-134a fittings are different sizes.
The one closest to the compressor appears to be the low-side and by the drier is the high-side.

[Porsche1987s]

OK, then the one in the first picture by the firewall is the low-side,

and the one in the second picture by the receiver-drier is the high-side.

[mattdavis11]

That's right. Don't turn the can upside down right away, turn it half way, then if you need it all, turn it up side down. Go slow. That's the suction line (low) and putting liquid straight to the compressor can mess up the valves inside the compressor. The 10P15's had weak enough valve plates to begin with.

[kuehl]

For a DIY, NEVER turn the refrigerant can upside down.
Only right side up.

Through the low side service port (smallest diameter on an R134a system)
on your firewall.

The refrigerant can should be right side up, engine running at idle. If you want to speed up the process place the can in a warm bucket of water (right side up) and raise the RPMs up a tad.

With R134a, your drier site glass may become cloudy and it can be difficult to tell if the system is fully charged.

Rule of thumb for R134a is 85% weight of the factory R12 specified charge.
Example, 2.25 lbs of R12 = 36 oz X .85 = 30.6 oz R134a