Battery cooling system service on the 2024 Model Y Performance involves draining and refilling the low-voltage/accessory cooling loop coolant. Note: the HV battery thermal loop, octovalve, superbottle, and heat pump are NOT serviceable outside Tesla — this procedure addresses only the accessible coolant reservoir/loop service that does not require disturbing HV components or orange cabling.

Warnings

Tools required

Parts

• Coolant reservoir cap (inspect, replace if seal degraded) × 1 — OEM-specified Model Y coolant reservoir cap
• Coolant hose clamps (replace any single-use spring clamps disturbed) × 4 — Manufacturer-specified spring clamp
• Underbody fastener clips (commonly damaged on removal) × 10 — Tesla-spec plastic push clip

Fluids

• Tesla Battery/Motor Coolant (G-48 specification, pre-mixed — DO NOT substitute non-G48 ethylene glycol) — 10 qt

Preparation

1. Park on level ground, place in P, engage parking brake.
2. Exit ALL doors with the key fob away from the vehicle. Wait at least 2 minutes for HV systems to fully de-energize, even on this non-HV job.
3. Disconnect the 12V low-voltage battery (located behind/under the rear seat area on 2024 Model Y — refer to Service Manual for exact access panel).
4. DO NOT touch, cut, or pierce ANY orange cable — these are high-voltage and lethal.
5. If at any point you encounter an orange cable, an HV component, or are unsure if a system is de-energized: STOP and consult a Tesla-certified technician.
6. Allow the vehicle to sit for at least 1 hour after driving so coolant is below 40°C before opening the system.
7. Place the vehicle in Jack Mode via the touchscreen BEFORE disconnecting 12V (suspension is coil on Model Y, but Jack Mode disables certain alerts).
8. Raise the vehicle on a lift using only Tesla-specified puck locations with adapters; do NOT lift on the battery case pinch seam.
9. Stage a coolant catch pan and confirm you have at least 10 qt of correct G-48 Tesla coolant before draining.

Procedure

1. 1

   Confirm scope of service
   Verify that the cooling work to be performed is limited to the accessible low-voltage cooling loop and reservoir — not the HV battery thermal loop, octovalve, superbottle, or heat pump. If any portion of the planned work requires disconnecting coolant lines from the HV battery pack, drive units, or thermal management module, STOP and refer to a Tesla service center.
   ⚠️Octovalve / heat pump / HV battery thermal loop service is NOT covered by this procedure.
2. 2

   Remove underbody aero panels for access
   Remove the front underbody aero shield using the appropriate Torx and plastic clip removal tools. Note clip locations and replace any broken clips on reassembly. Do not pry against the battery case or any orange-cabled component visible above.
3. 3

   Locate and inspect the coolant reservoir
   Locate the coolant expansion reservoir in the front trunk area. Inspect the cap, reservoir body, and visible hoses for cracks, weeping, or discoloration of coolant (rust, oil sheen, or sludge indicates internal contamination — STOP and escalate). Photograph hose routing before disturbing anything.
   ⚠Open the reservoir cap slowly to vent any residual pressure.
4. 4

   Drain old coolant
   Position the catch pan beneath the lowest accessible drain point of the cooling loop. Open the cooling system at the manufacturer-specified low-point drain or, if no drain plug is present, disconnect the lowest accessible coolant line from a non-HV component (e.g. front radiator return) using hose clamp pliers. Allow the system to drain fully — expect approximately 8-10 qt depending on what loops are opened. Capture all fluid; G-48 coolant is toxic and must be recycled.
   ⚠️Do NOT disconnect coolant lines that enter the HV battery pack, octovalve, or drive units.
   ⚠Coolant is harmful to pets and wildlife — contain spills immediately.
5. 5

   Inspect and replace serviceable cooling components
   While the system is drained, inspect accessible hoses for swelling, cracks, or chafing. Replace any compromised hoses with manufacturer-specified parts. If the radiator or accessory coolant pump is being replaced as part of this service, perform that replacement now using the manufacturer-specified mounting hardware.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)

   Coolant Line Fittings15 Nm (11 lb-ft)
6. 6

   Reconnect coolant lines
   Reinstall all coolant lines disconnected during draining. Use new spring clamps or replacement clamps where any were disturbed. Tighten any threaded coolant line fittings to specification. Confirm every connection is fully seated before proceeding.
   Torque spec

   Coolant Line Fittings15 Nm (11 lb-ft)
7. 7

   Vacuum fill the cooling system
   Connect a vacuum fill tool to the coolant reservoir. Pull a vacuum of approximately -25 inHg (or per tool manufacturer's spec) and hold for 5 minutes to verify the system holds vacuum (indicates no leaks). Then draw new G-48 Tesla coolant into the system under vacuum until the reservoir reaches the COLD FILL line. Do NOT use generic green or universal coolant.
   ⚠If vacuum drops during the hold test, there is a leak — locate and correct before filling.
8. 8

   Reinstall reservoir cap and underbody panels
   Install the reservoir cap to the manufacturer-specified torque (typically hand-tight to a defined click — refer to service manual). Reinstall underbody aero shields using new clips where required. Torque any cover/shield fasteners to specification.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
9. 9

   Reconnect 12V battery
   Reconnect the 12V low-voltage battery. Clean terminals before reattaching. Torque battery terminal bolts and the hold-down to specification. Reinstall any access panel and rear seat hardware.
   ⚠Vehicle will wake and may run thermal self-checks within seconds of reconnection — keep hands clear of fans and pumps.
   Torque spec

   Battery Terminal Bolts7 Nm (5 lb-ft)

   Battery Hold-Down Bolt11 Nm (8 lb-ft)

   Ground Cable Bolt14 Nm (10 lb-ft)
10. 10

    Bleed and burp the cooling system
    With the vehicle awake, allow Tesla's automatic thermal management to circulate coolant. Watch the reservoir level — it will drop as air purges. Top off with G-48 coolant to the COLD FILL line. Cycle climate control between max heat and max A/C to encourage the accessory loop to circulate. Allow at least 15-20 minutes of operation, rechecking and topping off until level is stable.
    ℹ️Tesla's thermal system runs pumps autonomously; you may hear them cycle even with the car 'off'.

Reassembly

1. Confirm all underbody panels are reinstalled with all clips and fasteners present.
2. Confirm the coolant reservoir cap is fully seated.
3. Confirm the 12V battery is reconnected, terminals torqued, and hold-down torqued.
4. Lower the vehicle from the lift.
5. Exit Jack Mode if previously enabled (it self-clears once the car drives off, but verify on the touchscreen).

Verification

• Start the vehicle and check the touchscreen for any thermal system, battery, or coolant-related alerts — there should be none.
• After a 10-15 minute drive, recheck the coolant reservoir level (cold) — it should remain at the COLD FILL line.
• Inspect all disturbed connections from below for any sign of weeping or drips after the test drive.
• Confirm cabin heat and A/C both function normally — abnormal performance can indicate trapped air or an octovalve issue (octovalve issues are dealer-only).
• Log this service date and odometer reading. Tesla recommends battery coolant inspection at 4 years / 50,000 mi — schedule the next inspection accordingly.
• While under the vehicle, take the opportunity to check tire wear — Model Y Performance wears tires quickly; Tesla recommends rotation every 6,250 mi.

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