Replacement of accessible low-voltage coolant lines (e.g., front cooling loop hoses to radiator, expansion bottle, and front motor cooling circuit) on a 2024 Model S Plaid. This procedure covers only non-HV coolant plumbing — any line connected to the HV battery pack, octovalve, superbottle, or drive unit internals requires Tesla Toolbox and is out of scope.

Warnings

Tools required

Parts

• Replacement coolant line(s) — manufacturer-specified for Model S Plaid × 1 — Refer to Tesla EPC by VIN
• Spring/worm hose clamps as required × 4 — OEM-spec replacement clamps
• O-rings / quick-connect seals for disconnected fittings × 1 — OEM-spec seal kit

Fluids

• Tesla Battery/Motor Coolant (G-48 equivalent) — 10 qt

Preparation

1. Park on level ground, place in P, and engage the parking brake.
2. Exit ALL doors with the key fob carried away from the vehicle. Wait at least 2 minutes for HV systems to fully de-energize, even on this non-HV job.
3. Open the frunk and disconnect the 12V (or 16V lithium, if equipped) low-voltage battery located under the frunk nose cowl panel. On 16V Plaid units verify the rear-seat auxiliary location per architecture notes.
4. Confirm the vehicle is fully powered down — no HVAC, no contactor clicks, no display activity.
5. Visually trace the coolant lines you plan to service. Confirm NONE of them lead to the HV battery pack, octovalve, superbottle, heat pump assembly, or drive unit housings. If any do, abort and refer to a Tesla-certified technician.
6. Allow the cooling system to cool to ambient temperature.
7. Raise the vehicle on a lift or jack stands using only Tesla-approved lift points (puck locations on the rocker pinch welds — use rubber pucks to protect the aluminum structure).
8. Remove the front underbody aero shield and any wheel-well liners required to access the target coolant lines.
9. Place a drain pan beneath the lowest point of the circuit being serviced.

Procedure

1. 1

   Identify and confirm scope of coolant lines
   Using the Tesla Service Manual diagram for this VIN, positively identify each coolant line to be replaced. Mark them with tape. Re-verify that none of the lines are part of the HV battery thermal loop, drive unit cooling, or heat pump/octovalve circuit. Only proceed with low-voltage accessory cooling lines (radiator-side hoses, expansion bottle hoses, and front cooling module plumbing not bonded to the HV system).
   ⚠️If unsure whether a line is HV-thermal-related, STOP. Contact a Tesla-certified tech.
2. 2

   Drain the coolant from the serviced circuit
   Locate the lowest accessible drain point or the lowest hose connection on the circuit being serviced. Slowly loosen the fitting or clamp to relieve any residual pressure, then fully disconnect to drain into the pan. Capture all coolant — do not allow it to contact painted aluminum panels for extended periods. Cap the expansion bottle once flow slows to control siphoning.
   ⚠Used Tesla coolant must be disposed of as hazardous waste per local regulation.
3. 3

   Remove obstructing covers and brackets
   Remove any plastic covers, air ducts, or sensor brackets that block access to the coolant line routing. Set fasteners aside in labeled trays. If a sensor (e.g., coolant temperature sensor) must be unbolted to access a line, disconnect its electrical connector first.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)

   Sensor Bolts11 Nm (8 lb-ft)
4. 4

   Disconnect quick-connect coolant fittings
   For Tesla quick-disconnect fittings, use the proper release tool — do NOT pry with screwdrivers, as the plastic collars are fragile and leak-prone if damaged. Depress the locking tabs evenly and pull straight off. Inspect each fitting and seal; replace any O-ring that shows deformation, cuts, or hardening.
   ⚠Damaged quick-connect fittings will leak intermittently and are extremely difficult to diagnose later. Replace any that show stress cracks.
5. 5

   Loosen and remove hose clamps
   For spring or worm-gear clamped hose ends, use hose clamp pliers to slide spring clamps clear of the bead, or unscrew worm clamps. Twist the hose gently to break the seal — do not pry against aluminum fittings, as gouging the sealing surface will cause persistent leaks.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)
6. 6

   Remove coolant line mounting brackets
   Unbolt any chassis-mounted brackets retaining the coolant line along its run. Note routing carefully — take photos before removal. Coolant lines on the Model S follow specific routing to clear suspension, steering, and HV cabling; incorrect routing can cause chafing failures.
   ⚠️If a bracket also retains an orange HV cable, do NOT disturb the HV cable. Work around it or stop.
   Torque spec

   Bracket Bolts20 Nm (15 lb-ft)

   Mounting Bolts27 Nm (20 lb-ft)
7. 7

   Remove the old coolant line
   Carefully extract the line from the vehicle. Be mindful of overhead HV cabling, A/C lines, and aluminum body structure. Do not force the line — if it snags, investigate before pulling.
8. 8

   Install the new coolant line
   Compare the new line to the old one for length, bend angles, and fitting orientation. Route exactly as the original, securing into any factory clips or guides. Ensure no contact with sharp edges, suspension travel paths, or HV cabling.
9. 9

   Reattach fittings and clamps
   Lubricate new O-rings with a small amount of fresh coolant before installation. Push quick-connects together until you hear/feel the lock engage, then tug gently to confirm engagement. Position spring/worm clamps over the bead at the factory location and tighten to spec.
   Torque spec

   Coolant Line Fittings15 Nm (11 lb-ft)

   Hose Clamps3 Nm (2 lb-ft)
10. 10

    Reinstall brackets, sensors, and covers
    Reinstall any brackets, sensor mounts, and covers removed for access. Reconnect any sensor electrical connectors and ensure they click fully home.
    Torque spec

    Bracket Bolts20 Nm (15 lb-ft)

    Mounting Bolts27 Nm (20 lb-ft)

    Sensor Bolts11 Nm (8 lb-ft)

    Cover Screws11 Nm (8 lb-ft)

    Connector Bolts7 Nm (5 lb-ft)
11. 11

    Refill and vacuum-bleed the coolant system
    Connect a vacuum fill tool to the expansion bottle. Pull the system to at least -25 inHg and hold for 5 minutes — the gauge must remain steady, confirming a leak-free system. Then draw fresh Tesla-spec G-48-equivalent coolant into the system under vacuum until full. Top off the expansion bottle to the cold-fill mark.
    ⚠Air pockets in EV coolant systems cause poor thermal performance and intermittent fault codes. Vacuum fill is mandatory — do not gravity-fill.
12. 12

    Reconnect the low-voltage battery
    Reconnect the 12V/16V low-voltage battery in the frunk (or rear seat for 16V Plaid units). Torque the terminal to OEM specification — refer to Tesla Service Manual. Close the frunk.

Reassembly

1. Reinstall the front underbody aero shield and any wheel-well liners removed for access — torque to OEM specification per Service Manual.
2. Lower the vehicle to the ground using approved lift points only.
3. Wake the vehicle and allow systems to fully boot. Confirm no thermal-system fault alerts on the center display.
4. Run the HVAC system on max cooling and max heat in sequence to circulate coolant through accessory loops, then re-check the expansion bottle level after the system reaches operating temperature and cools again.

Verification

• Inspect every disturbed fitting and clamp for leaks after a 15-minute idle and again after a short test drive.
• Verify no coolant-related alerts (e.g., low coolant, thermal system faults) appear on the center display over a full drive cycle.
• Confirm cabin HVAC heating and cooling perform normally — performance issues here often indicate trapped air.
• Re-check expansion bottle level the following day when fully cold; top off with Tesla-spec coolant only if needed.
• Document service date: Tesla recommends battery coolant system inspection every 4 years / 50,000 mi — schedule the next inspection accordingly.
• If any quick-connect fitting weeps even slightly, replace it — Tesla coolant fittings either seal fully or fail; there is no acceptable seepage.

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