Where is the low pressure port on a 1987 Mercedes 420 SEL to recharge with freon?

On a 1987 Mercedes 420 SEL, the low-pressure port for recharging the air conditioning system with freon is typically located on the receiver-drier, which is found near the front of the engine compartment. Look for a service port with a cap that is usually marked with an "L" or is smaller in diameter compared to the high-pressure port. Ensure the engine is off before attempting to recharge and use the correct refrigerant type specified for the vehicle.