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.
Visual inspection
2010 Mercury Mariner Hybrid, AWDSECTION Visual inspection
WARNING: This page is about a different car, the 2005 Mercury Montego, 2005 Ford Freestyle, and 2005 Ford Five Hundred. However, it is still accessible from the selected car via links, so may be relevant.
- Open the hood and visually inspect the heating and air conditioning systems for the following:
- Coolant reservoir for correct coolant level
- Heater hoses for deterioration or loose connections
- Radiator and condenser for foreign material or damaged fins restricting airflow, loose mounting or connections
- Accessory drive belt(s) and cooling fan(s) for wear or physical damage
- Refrigerant lines and connections for physical damage or loose connections
- Compressor for physical damage or loose connections
- Suction accumulator (if equipped) or receiver/drier (if equipped) for physical damage or loose connections
- Wiring and connectors for excessive wear, loose or damaged connections, or incorrect routing
- Carry out air conditioning refrigerant analysis. For additional information, refer to REFRIGERANT IDENTIFICATION TESTING .
- If the refrigerant fails the analysis, discontinue diagnosis and make recommendations for repairs.
- If the refrigerant passes the analysis, carry out the air conditioning system check.
- Check the air conditioning system.
- Connect an R-134a manifold gauge set or refrigerant service center with gauges to the refrigerant system.
- With the vehicle in PARK, parking brake set, thermometer installed in center panel vent, and air conditioning system on and set to MAX A/C (if equipped) or FULL COOL and RECIRC (if equipped), start the engine.
- Record the air refrigerant system pressures while running the engine at 1,500 rpm and allow the engine to return to idle.
- Operate the blower motor in all control positions and check for correct blower speed changes.
- With the blower motor on MED HI, operate the air discharge mode selector in all positions and check for correct airflow in each position.
- Operate the temperature blend selector in all positions and check for correct change in discharge temperature. Check the air discharge temperature with the selector in the coolest position and the air conditioning on and set to MAX A/C (if equipped) or FULL COOL and RECIRC (if equipped) to determine if the air discharge temperature is acceptable for the current ambient air temperature.
- Carry out the ATC self-test (if applicable).
If the refrigerant system pressures were low, carry out the refrigerant system leak test.
- Use either an ultraviolet (UV) or an electronic leak detector to check for leaks at all refrigerant lines, connections, and components.
- After all tests have been completed, report all findings and recommended repairs to your service advisor before carrying out further diagnostic procedures.
A/C refrigerant analysis
Air conditioning system check
Refrigerant system leak test
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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.