I have had all sorts of A/C woes. Last year my mechanic had to tear the system apart to replace the compressor, rusty accumulator & orifice tube, along with various o-rings.

Now, it's leaking compressor oil at the coupling between the evaporator and high pressure pipe. Not badly--the A/C still has refrigerant even a few months since its recharge. The dealer tried replacing the o-ring, but it still leaks. They said the evaporator isn't a Volvo part since the pipes are copper (must have been replaced before I got the car), and they said since the high pressure pipe is a Volvo part, the 2 can't fit together perfectly, hence the leak. But the system was leak-free for several years before the problems last summer. Any ideas short of replacing the evaporator with a Volvo one?

Is this something I should just put up with? Are there any sealants I can glob all over the coupling or something to keep the oil in? Thanks for your help!