I installed a new ACM condenser last summer, thinking that ACM was oem. Since then I have found out that in fact Behr is oem. The structure of the condensers is completely different (besides fittings). The original Behr that I took out of my 83 300sd had smaller tubing running through the fins, however it had a lot more tubes. The Behr has 48 pipes through the fins; the ACM has only 30 pipes though the fins. Also the fin structure is completely different. The Behr has extremely thin and dense fins (tightly placed) fins; the ACM has much thicker fins and they are spaced much farther apart. I'm guessing that there are two possibilities. Either the ACM has been designed to be more compatible with the higher pressures of r134, or else it has just been made cheaply and is of inferior quality. I would love to know what the performance differences are between the two condensers. Living in Palm Springs, I need the max performance that I can get with the original r12 Freon.

I have a hunch that oem parts are the way to go with r12.