R22 is a HCFC refrigerant and R134a is an HFC refrigerant.
R-22 and R-134a are not compatible refrigerants and should not be mixed.
If you put R-22 in an empty R-134a system, it can cause damage to the system, including the compressor, evaporator, and condenser.
Therefore, it is important to use the correct refrigerant for your vehicle's air conditioning system.