I'm fixing my A/C tomorrow (or going to start) and I was wondering that when I hook up vacuum can I do it only on the low pressure side? Or do I have to hook up both the high and low pressure side? The reason I ask is that the high pressure side is so hard to get to on my 82 300SD.

Also, I have r12 and was wondering if I should break down and buy a good oil or just use mineral oil? I was told by an A/C tech that not all oils for R12 are compatible.

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1982 300SD
1967 250S
...what was I thinking......

Hook up both sides. If you have a blockage you could get an artificially low reading if you only pull on one side. You should get the best picture of your system if you pull on both sides. Harbor Freight has a pretty inexpensive set of gauges if you need them.

The high side is right in front of the engine. Are you sure you don't mean the low side? That's the one on the larger hose near the brake booster...

With respect to oil, mineral oil is good oil for R-12. Some has encouraged using synthetic oil, with the idea that it can be used by both R-12 and R-134a, but since I will never convert to R134a , I don't see the point.

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Tjohn

82 300 SD
77 450 SL (gone)

I thought the high side was under the car? Maybe I'm thinking of a different model.

__________________
1982 300SD
1967 250S
...what was I thinking......