Supplying Climate Control Systems to the Vehicle Market for Over Half a Century.

System Oil Allowance


All Evans R-134a Air Conditioning Systems currently supplied to the vehicle industry use PAG oil as the system lubricant. This oil is completely different than the mineral oil used in R-12 systems. PAG oil must never be used in an R-12 system, and mineral oil must never be used in an R-134a system. Use of an incorrect oil can cause serious A/C system damage, and will void warranty coverage. When an air conditioning system is serviced, it is important to maintain the original quantity and type of oil within the A/C system. Oil type and total system quantity will be listed on the compressor data label attached to the compressor body. If additional oil is determined to be necessary, only use the exact oil type and viscosity shown on the compressor label. Do not mix oil brands or types. Ford, GM, Workhorse, and other OEMs supply and warrant their own vehicle A/C compressors. They also supply their own specified compressor oil, which is available through the standard dealer network.

There are only three situations that justify adding oil to an A/C system:

  1. Replacing oil that was removed in the refrigerant recovery process. Measure oil quantity that settled in the oil-catch bottle of the recovery machine. Add an equal quantity of new oil back into the A/C system.
  2. Replacing oil that was removed with a defective system component. Add an equal quantity of new oil back into the A/C system.
  3. Replacing oil lost due to a system damage or severe leakage. This lost oil will be visible on or around a damaged or leaking component. Only add new oil if more than 1-2 ounces is believed to have been lost.

The quantity of oil typically removed with a replaced component is shown below:

Compressor: Drain and measure oil from old compressor. Typically 2-4 ounces will be found. Drain and refill new compressor with new oil, using the same quantity found in the old compressor. Use a minimum of 2 ounces in the new compressor. Never add more than 8 ounces to a new compressor, to avoid compressor start-up damage.
Condenser: 2 ounces
Receiver-Drier: 1 ounce
Evaporator: 1 ounce
System Hoses*: Typically None - Drain and Measure
*Systems with hoses 15 feet or longer, contact Evans for assistance.

Return to Troubleshooting, Diagnosis and Repair

Return to Technical Support > Home