Hello everyone,

I have a 1983 300SD with weak A/C. The other day, I decided to hook up my manifold set and check the pressures. With the system running, I was getting around 30PSI on the low side at idle. I added some R134a up to about 38-40PSI and there was no real noticeable difference. I noticed the high side pressure is only around 120PSI; I was expecting to see a much higher pressure here. The air blows out cooler than than ambient temperature but not enough to effectively cool the car on a hot day. It was about 80F out when I charged the system. It gets a little cooler while driving on the highway but that is to be expected.

So, what can I do to get better cooling aside from running propane or finding R12? Could the expansion valve/orifice tube account for the high side not being that high? Am I off my rocker or what?

Thanks for any help.

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1991 F250 super-cab 7.3 IDI. (rebuilt by me) Banks Sidewinder turbo, hydroboost brakes, new IP and injectors.
2003 S430 - 107K
1983 300SD - Tanoshii - mostly restored ~400K+.
1983 300SD - Good interior. Engine finally tamed ~250K.
Monark Nozzle Install Video - http://tinyurl.com/ptd2tge