Abstract: A composition is disclosed for preventing and repairing leaks, and lubricating gaskets and o-rings, preferably for use in a motor vehicle air conditioning system. The composition preferably includes a fluorocarbon resin mixed a dye. Mineral oil for R-12 refrigerant systems or ester oil for R-134a refrigerant systems can also be added to the mixture. The composition is preferably installed with an air conditioning oil injector through the low pressure side service port of the air conditioning system. When using the product, it is not required to evacuate the air conditioning system. The oil injector containing the composition is connected to the low pressure side service port, the motor vehicle engine is started, the air conditioning system is set to maximum cooling and the system recharged with either R-12 or R-134a refrigerant. The relevant leaks are sealed by composition which also lubricates rubber parts of the air conditioning system.