EV Coolant Lines

Replace EV coolant lines on a 2012 Tesla Roadster. Note: the Roadster's cooling system services the PEM (Power Electronics Module), motor, and battery (ESS) loops — any line directly attached to the ESS or PEM internals requires HV-trained service. This procedure covers accessible chassis coolant lines only.

Warnings

Tools required

Parts

• Replacement EV coolant line(s) — manufacturer-specified for Roadster 2.x × 1 — Refer to Tesla Roadster parts catalog — many Roadster coolant lines are model-specific
• Hose clamps (replace any disturbed spring or worm-gear clamps) × 4 — OEM-equivalent size to match line OD
• O-rings / quick-connect seals (if line uses quick-disconnect fittings) × 2 — OEM specification

Fluids

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

Preparation

1. Park on level ground, place transmission in neutral or 1st gear (manual), and engage the parking brake. Chock the wheels.
2. Exit the vehicle with the key fob and place it at least 10 ft away. Wait at least 2 minutes for HV systems to fully de-energize, even on this non-HV job.
3. Open the front trunk/access panel and disconnect the 12V auxiliary battery (negative terminal first). On the Roadster, the 12V is typically in the front compartment — refer to owner documentation for exact location.
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 cool fully — coolant system can be hot and pressurized after driving or charging.
7. Raise the vehicle on a lift or jack stands using the manufacturer-specified jacking points (Roadster has dedicated jack pads; do not lift on the bonded aluminum tub directly).
8. Identify the specific coolant line(s) being replaced and confirm both ends terminate at serviceable components (radiator, expansion tank, coolant pump, hose junctions) — NOT inside the ESS or PEM.

Procedure

1. 1

   Identify circuit and isolate scope
   The Roadster has separate cooling loops for the PEM/motor and for the ESS battery pack. Identify which loop the failed line belongs to. Confirm the line endpoints are external (radiator, hose tee, expansion bottle, external pump). If either endpoint enters the ESS enclosure or PEM housing, abort this procedure and refer to a Tesla-certified technician.
   ⚠️Lines entering the HV battery (ESS) or PEM are not user-serviceable.
2. 2

   Remove access panels and underbody trim
   Remove any underbody diffuser panels, side covers, or rear clamshell access panels needed to expose the coolant line. Use trim tools and document fastener locations. Keep cover screws organized.
   Torque spec

   Cover Screws11 Nm (8 lb-ft)
3. 3

   Drain the affected coolant loop
   Position a clean drain pan under the lowest point of the affected loop. Open the drain (or loosen the lowest hose clamp on a non-HV portion of the loop) and allow coolant to drain completely. Capture all fluid — Tesla G-48 coolant should be recycled, not poured on the ground. Approximately 10 qt total system capacity; partial drain may be possible if isolating one loop.
   ⚠Do not drain by disconnecting a fitting at the ESS or PEM. Drain only at an external low point.
4. 4

   Relieve residual pressure
   Slowly open the expansion tank cap (only after the system has cooled) to relieve any remaining pressure and allow the loop to drain freely.
5. 5

   Photograph routing and clip positions
   Before removing the line, take detailed photos of the routing path, every retaining clip, every clamp orientation, and the proximity of the line to any orange HV cabling. Roadster routing is tight and incorrect re-routing can cause chafing against HV cable insulation.
   ⚠Note any standoffs that hold the coolant line away from orange HV cables — these MUST be reinstalled.
6. 6

   Release retaining clips and brackets
   Remove the bolts securing any line brackets along the chassis. Release plastic P-clips and push-pin retainers. Set hardware aside grouped by location.
   Torque spec

   Bracket Bolts20 Nm (15 lb-ft)
7. 7

   Disconnect line fittings
   At each end of the line, disconnect the fitting. For threaded fittings, use a backup wrench on the stationary side to avoid twisting downstream tubing. For hose-clamp connections, release the clamp and twist the hose gently to break the seal. For quick-connects, depress the locking tabs squarely — do not pry. Cap or plug open fittings immediately to prevent contamination.
   ⚠Do not yank lines free — hardline sections can deform and become impossible to reseal.
8. 8

   Remove the old coolant line
   Carefully extract the line from its routing path, taking note of how it weaves around the chassis, suspension, and any HV cabling. Maintain clearance from orange cables at all times.
9. 9

   Inspect mating surfaces and replace seals
   Inspect each fitting mating surface for corrosion, scoring, or coolant residue buildup. Clean with a lint-free rag. Replace any O-rings or sealing washers that were disturbed. Do not reuse crush-style seals.
10. 10

    Install the new coolant line
    Route the new line along the original path, reinstalling all standoffs and clips that maintain separation from HV cabling and moving suspension components. Hand-start all fittings to avoid cross-threading.
    ⚠Verify the new line does not contact any orange HV cable, exhaust-adjacent surface, or moving driveshaft component.
11. 11

    Torque fittings and clamps
    Torque threaded coolant line fittings to spec. Tighten hose clamps to spec — do not overtighten worm-gear clamps as this can cut into rubber hose. Torque mounting brackets and any structural fasteners disturbed during access.
    Torque spec

    Coolant Line Fittings15 Nm (11 lb-ft)

    Hose Clamps3 Nm (2 lb-ft)

    Bracket Bolts20 Nm (15 lb-ft)

    Mounting Bolts27 Nm (20 lb-ft)
12. 12

    Reinstall sensor and connector hardware (if disturbed)
    If any coolant temperature sensors or electrical connectors were removed for access, reinstall and torque them. Any fastener not on the verified list should be torqued to OEM specification — refer to Tesla Service Manual.
    Torque spec

    Sensor Bolts11 Nm (8 lb-ft)

    Connector Bolts7 Nm (5 lb-ft)
13. 13

    Refill and bleed the cooling system
    Refill the affected loop with Tesla Battery/Motor Coolant (G-48). Use a vacuum fill tool if available — the Roadster cooling circuit has high points that can trap air, leading to poor pack thermal management. Otherwise, fill slowly through the expansion tank and follow the Roadster service manual bleed sequence (typically involves running the coolant pumps with the cap off and topping up).
    ⚠Never use tap water or non-G-48 coolant — incompatible chemistry can damage the ESS cooling channels.

Reassembly

1. Reinstall any underbody panels, diffuser, and access covers using their original fasteners; torque cover screws to spec.
2. Reconnect the 12V auxiliary battery (positive first, then negative).
3. Verify expansion tank coolant level is at the COLD fill mark.
4. Clean any spilled coolant from the chassis — G-48 will leave a residue that can be mistaken for new leaks during inspection.

Verification

• With the system cold, confirm coolant level is at the COLD mark on the expansion tank.
• Power up the vehicle (ready mode) and allow the thermal management system to circulate coolant. Monitor for several minutes.
• Inspect every disturbed fitting and clamp for weeping or seepage. Re-check after a short test drive once the system has reached operating temperature and pressurized.
• Verify no contact between the new coolant line and any orange HV cable, suspension, or rotating component.
• Top off the expansion tank as air purges from the system over the next several heat cycles.
• Record the service date and mileage. Tesla now recommends battery coolant inspection at 4 years / 50,000 mi — log this service against that interval.
• If the vehicle shows any battery thermal warning, charging derate, or coolant-related fault on the VDS/instrument cluster, stop driving and consult a Roadster-experienced technician.

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

Chasing one of these codes and not sure which part is guilty? Ask a master mechanic about YOUR car →

More procedures for this vehicle