2018 Tesla Model S — A/C Refrigerant & Oil Specs

Quick answer

• Refrigerant: R-134a (most 2018 Model S). Some 2014+ vehicles transitioned to R‑1234yf, but 2018 Model S is typically R‑134a. Always verify the under‑hood label.
• Total system charge: About 850 g (30 oz) of R‑134a is common. Actual spec varies by condenser/chiller revisions; some labels list ~750–900 g. Charge strictly to the vehicle label by weight.
• Compressor oil: DENSO ND‑11 (POE, non‑conductive). Do NOT use PAG oil (PAG 46/100/150 are not approved for Tesla HV compressors).
• Oil quantity: Compressor is typically pre‑filled; Tesla does not publish a universal “add” amount. Typical total system oil is approximately 150 mL (≈5 oz), but follow the Tesla service manual/component replacement chart and the compressor tag.
• Service ports: Low‑side port is on the large‑diameter suction line near the electric A/C compressor at the right‑front of the vehicle (access generally under the frunk trim). High‑side port is on the small‑diameter liquid/discharge line near the condenser/receiver in the front core support area. Trim removal may be required for access.

Why R-1234yf matters

Many 2014+ vehicles use R‑1234yf. It’s more environmentally friendly but significantly more expensive than R‑134a and requires dedicated recovery/recharge machines, unique couplers, and SAE‑certified service equipment. While the 2018 Model S commonly uses R‑134a, always read the refrigerant label before servicing—charging the wrong refrigerant can damage components and is illegal. If your Tesla is labeled for R‑1234yf, you must service it only with yf and with an SAE J2843‑compliant machine.

Recharge procedure (high‑level)

• Identify and verify: Read the under‑hood label for the exact refrigerant type and charge weight. Confirm ND‑11 POE oil specification. Do not mix refrigerants or oils.
• Recover: Properly recover any remaining refrigerant with an approved machine dedicated to the correct refrigerant. Avoid cross‑contamination.
• Evacuate: Repair leaks first. Replace any disturbed O‑rings with the correct material. Pull a deep vacuum (target ~500 microns) and verify it holds to confirm system integrity.
• Charge by weight: Charge the exact weight shown on the vehicle label using a calibrated scale. Do not “top off” by pressure—Tesla systems are sensitive to charge accuracy because they also cool the battery via a chiller.
• Oil handling: Use only ND‑11 (POE) oil in this high‑voltage electric compressor system. If a component is replaced, add only the amount specified by the Tesla service procedure for that component. Keep tools/hoses dedicated to ND‑11 to prevent PAG contamination.
• Functional check: With high‑voltage systems enabled and adequate state of charge, confirm cabin vent temperature, condenser fan operation, and that pressures/temperatures stabilize. Use a scan tool for HVAC fault codes and compressor speed/current.

Important EV safety notes: Always follow Tesla’s HV disable procedure before opening the A/C circuit or working near the compressor/inverter assembly. Many operations require Tesla Toolbox access and service information.

Common A/C problems for this generation

• Condenser leaks/impact damage: The front condenser/receiver is vulnerable to road debris; leaks here are common and can lead to low charge performance.
• Service port core leaks and O‑ring seepage: Especially after multiple connections; replace cores and O‑rings when needed.
• Battery chiller or line leaks: The refrigerant circuit also cools the glycol loop. Leaks at the chiller or manifold connections can mimic typical cabin A/C leaks but impact battery thermal management too.
• Compressor faults: The high‑voltage electric scroll compressor can set isolation or over‑current faults if contaminated with PAG oil or moisture. Use only ND‑11 and observe strict cleanliness.
• Evaporator odor or reduced airflow: Cabin filters clog quickly; replace on schedule. Evaporator leaks are less common but possible.
• Airflow/heat exchanger blockage: Dirt buildup on the condenser/radiators reduces performance; inspect and clean as needed.

OEM service info

Tesla provides step‑by‑step HVAC and high‑voltage safety procedures via its official service information (Toolbox). Access to Toolbox and certain calibrations may be required after component replacement. Always refer to the exact VIN‑specific refrigerant label and Tesla service documentation for charge weight, oil balancing, and HV disable/enable steps.

When to call a pro

• You need to open the refrigerant circuit or replace the compressor/chiller.
• You don’t have an R‑134a (or yf, if labeled) recovery machine with a certified scale.
• Any high‑voltage warnings, isolation faults, or A/C‑related DTCs are present.
• The system was previously serviced with unknown oil/refrigerant.

Safety disclaimer: Servicing mobile A/C requires EPA Section 609 certification and, on EVs, high‑voltage safety training. Using the wrong refrigerant or oil (especially PAG in a Tesla) can cause expensive damage and safety hazards.

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