You should not attempt to determine this yourself. The correct amount is specified by the compressor manufacturer and is usually found:
* On the compressor itself: Look for a label or marking on the compressor indicating the proper amount of oil.
* In the A/C compressor's specifications: If you know the make and model of your compressor, you can look up its specifications online or in a repair manual.
* In a service manual for your vehicle: A factory service manual will detail the correct procedure and oil quantity for your specific truck.
Improperly adding oil can severely damage your A/C system. Too little oil leads to compressor failure, while too much can cause excessive pressure and damage other components.
Recommendation: Take your vehicle to a qualified A/C technician. They have the tools and knowledge to properly evacuate, recharge, and add the correct amount of oil to your system. This is a relatively inexpensive repair compared to the cost of a new compressor or other damaged components resulting from incorrect oil levels.
