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.
Refrigerant Circuit, General Precautions: Notes
- Follow the instructions for the workplace. They should be displayed in the workplace.
- Ensure absolute cleanliness when working.
- Wear work clothing, safety goggles and gloves when working with refrigerant and nitrogen.
- Turn on the exhaust gas ventilation system
- Use service station to discharge refrigerant circuit, only then open screw connections and replace malfunctioning components.
- Use caps to seal off opened assemblies and hoses to prevent ingress of moisture and dirt.
- Make exclusive use of tools and materials intended for refrigerant R134a.
- Be sure to close the container to prevent the refrigerant from absorbing moisture from the air.
-- Refrigerant Circuit, Flushing with Compressed Air and Nitrogen, refer to REFRIGERANT CIRCUIT, FLUSHING WITH COMPRESSED AIR AND NITROGEN .
-- Flush the refrigerant circuit with R134a refrigerant, refer to REFRIGERANT CIRCUIT, FLUSHING (CLEANING) WITH REFRIGERANT R134A
On vehicles with A/C compressor without magnetic clutch:
The engine should only be started after assembling the refrigerant circuit.
If possible start engine only with a filled refrigerant circuit.
The A/C compressor is always driven by the ribbed belt pulley/torsion elastic clutch. It does not have a magnetic clutch.
If an A/C compressor locks-up the overload protection for the A/C compressor shaft is triggered. If no bumps are visible on the ribbed belt pulley/overload protection, the A/C compressor may be blocked. Another indicator is abraded rubber material in the area of the ribbed belt pulley/overload protection.
The A/C compressor is equipped with a protected oil supply, this prevents A/C compressor damage in the event that the system is empty. This means that approximately 40 to 50 cm3 of refrigerant oil remains in the A/C compressor.
The engine may only be started when the refrigerant circuit is installed correctly. For example; if the refrigerant pipes are not connected to A/C compressor, when the engine is running the A/C compressor may heat up (via internal heat generation) so much that the A/C compressor will be damaged.
A/C Compressor Regulator Valve -N280- is not activated when the refrigerant circuit is empty and the A/C compressor idles with the engine.
If it is necessary to start the engine with a discharged refrigerant circuit:
Refrigerant circuit must be fully assembled.
At least a quarter of the prescribed refrigerant oil must be in the A/C compressor.
Do not let the engine RPM go above 2, 000.
The engine should run less than 10 minutes.
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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.