Air conditioning intermittently not cooling
Watch out for all Mercedes with poor operating a/c. The refrigerant hoses contain an internal vinyl sleeve. This sleeve can come loose from the rubber line and can cause a permanent or occasional restriction.
If the low side pressure is noticeably high, use an infrared temp gun to check for a temperature drop in the line.
If you have a temperature drop in a line that shouldn’t have one, this may be your problem.
Hello Josep, R134a systems use barrier hoses with a liner. This could happen to any R134a system. It looks like damage from some sort of additive, most likely a seal conditioner that is supposed to stop leaks in the system by swelling the O-rings. These "Wonder Cure" additives cause all kinds of damage to A/C systems, unfortunately the damage takes a while to manifest itself. So someone adds