All, I have searched for a temperature/pressure chart for a W124 R-12 system and can only find reference to a ~40 degree temp delta. Anyone know where one can be located? I just repaired a leak on my '90 300e. I bought a vac pump, evacuated the system, left it overnight at 27", still same reading in the morning. I got 2 14oz. cans of R-12 in her, the third can ruptured while adding, so I think I am still low. Sticker calls for 1.1kg coolant. My high side runs up to 250, then the fans kick on and drops to 180, repeats the process. Low side ~35. I was getting 58 degrees vent temp at 89 outside temp.

2.2 lbs times 16 ounces per pound = 35 ounces
You put in 14 times 2 = 28
Now about how much did you get in on that last can?
Anything less than 7 ounces or half of your last can, and you are low.

It is an R12 system, so just look at the sight glass...

By the way, Im in Phoenix too and also about half a can low. Same temp and gauge readings, just dont want to crack another can and only use half. Ill split one with ya

The p/t chart for this car is in section 83-608 of the MB service manual.

If you are getting 58 degrees with windows up you're way off. If it is with windows open, which is the way that MB indicates in their charging instructions you are only about 3 degrees off. Since that is the only charging instruction I've ever seen asking for open windows, I expect that you have closed windows. In that case you are way off.

You need that other half can of refrigerant in there and a clear sight glass.

Good luck,