How many cans of R-134 do I need?
 

I have searched and found that R-134 should be charged to 85% of an R-12 system. What does this equate to in cans? I have a 1982 240D. I evacuated the system and it is converted to R-134. I put in three cans. My high side gauge only shows around 60 pounds. I am not trusting my gauges. It blows cold but the compressor is noisy. I think I might have to replace that. Also, is there and orifice tube in these systems? If so, where? Thanks, Paul

Check your sticker under the hood. My SD says 2.9lbs for R12. Not sure what your car takes but you can easily do the math. Just plug in your R12 weight in place of 2.9 below.

2.9lbs x 16 oz/ 1 lb = 46.4 oz

46.4 oz x .85 = 39.44 oz

39.44 oz /12oz in 1 can = 3.29 cans

I know this has been debated - The conversion INFO I have used said 10% less 134A when moving from R12

Wow, after 3 cans your high side should be in the 150-250 range, depending on temperature. R-134a will have higher pressures.
If your air is cold then I question your gauges as I can't imagine the air being cold with a high side pressure in the 60's.........
No orifice tube on these, they use an expansion valve. Yours will be located behind the glove box.
How much oil did you add to the system? With R134a I think the R4 compressor calls for Pag-150 [150 is viscosity].

Don't use PAG for a conversion, unless you replace the compressor and all rubber parts.

Search some more and you will likely decide that R-134a isn't going to be an effective solution to your a/c problems, especially in LA.

ok, if your a/c is clunking, AND you have not replaced the expansion valve. I'd strongly recommend purging your system, replacing the reciever, the expansion valve, and prior to installation of these parts, I'd flush all the lines. then replace and see how it looks. also, 134 is not going to remain long in old 12 rated flex lines. at a minimum, you are going to need new orings and a flush.
also, if your compressor is already knocking... you better replace it now. a perfectly good R4 compressor will fail running 134a pressures. and it's much easier to flush and change a compressor BEFORE it fails and blows chunks throughout the system!!!

It is possible to install an aftermarket filter ... given what has been said ... and I agree totally.... with your compressor already making noise you could save a lot of trouble if you put in the filter before it blows and puts particles downstream....will not make it work longer... but will shorten the cleanup and replacement afterwards...

The filter should be close to the output of the compressor...before the condensor... you are trying to keep the condensor ' clean' in the event of really bad situation....
Since you did not follow usual recommended procedure... as mentioned above.... you may have some problem cleaning up your system well enough that your next good compressor will have a long life... lots of good threads on this forum and on Aircondition.com others... most of the philosophy of cleanliness applies to all AC systems...