My A/C has developed a nice rattle. I have done the following: Cleaned the filter. Pulled the squirrel cage, cleaned and check the motor and fan for tighteness. Tapped on the heat exchangers. Tested the blower while laying it on the floor. No rattles turned up. Reassembled everything, No rattles with the fan running. A/C kicks on - Rattle! :wall: Pulled the Plenum last night. Cleaned off the dust inside the condenser Tapped on various sheet metal parts. Nothing. Click the blower on. Nothing. Click the A/C on............ Rattle. :wall: Coming directly from the A coil. The lower coils a super cold, the uppers not as cold. Thinking I might need a recharge.............. Unit is 12 years old, and never touched. Comments, questions, concerns? Help!!!!

Is it ok for the external box of a fixed split air conditioner to be put on my flat roof that gets the sun the whole day? Does it affect the cooling ability or will it be able to cope? Should I point the fan away from the sun?