Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Air Conditioning (A/C) System Leak Test Using Forming Gas
For information on Ford Color Coded Illustrations refer to OEM COLOR CODING INFORMATION
Special Tool(s) / General Equipment
| Forming Gas Pressure Gauge and Leak Detector |
|---|
Materials
| Name | Specification |
|---|---|
| Forming Gas | - |
Leak detection
All vehicles
-
NOTE: Use a Rotunda-approved Tracer Gas A/C System Dealership Leak Detection Service Kit that meets SAE J2790.
Recover the refrigerant. Refer to the appropriate Recovery procedure in GENERAL PROCEDURES .
Hybrid\Electric vehicles
- Electric or Hybrid vehicle with a battery chiller. It may be necessary to activate the battery chiller(s) to open the solenoid(s) to allow vacuum and gas to pass through to chiller for leak testing. Refer to service informationrefrigerant reclaim and charging to see if solenoid(s) activation is necessary. Follow the service information procedure to perform activation if needed.
All vehicles
- Perform the vacuum leak test in accordance with the service unit manufacturer instructions.
- Assemble tracer gas leak detection kit per manufacturer instructions.
- Connect the forming gas pressure gauge and leak detector service hose to the high-pressure port of the air conditioning system in accordance with the manufacturer instructions. Use the General Equipment: Forming Gas Pressure Gauge and Leak Detector
Material
: Forming Gas
-
NOTE: Make sure that the pressure reducer (2) is closed.
- Open the bottle valve.
- Slowly turn the pressure reducer until a pressure of 4.1 bar (60 psi) is reached. Maintain open for 30 seconds to allow tracer gas to fill system.
- Close the bottle valve.
- Model D740KIT - Tracer Gas A\C System Dealership Leak Detection Service Kit
- Leak test the refrigerant system. Follow the instructions included with the Leak Detector for handling and operation techniques.
- D740 H2/N2 leak detector
-
NOTE: Trace gas is lighter than air, and tends to move up from the source of the leak. It is possible that a leak may not be detected if the leak detector tip is held below the leaking fitting, line or component. Always be sure to thoroughly leak test below, above and around the fitting, line or component.
Disconnect the forming gas pressure gauge and leak detector from the air conditioning system in accordance with the manufacturer instructions.
-
NOTE: Do not ever recover the tracer gas into the A/C recovery/charging machine.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.