Replacement of the EV coolant pump on a 2012 Tesla Roadster. This is a PROFESSIONAL-ONLY procedure — the Roadster's cooling system is tied to the HV battery's PEM/ESS thermal loop, and improper service can damage the ~$15,000+ HV battery pack. Note that Tesla now recommends battery coolant inspection at 4 years / 50,000 miles.

Warnings

Tools required

Parts

• EV coolant pump (manufacturer-specified for 2012 Roadster) × 1 — Refer to Tesla Roadster parts catalog — do not substitute a generic Bosch/Pierburg pump without verification
• Coolant hose clamps (if single-use spring clamps) × 2 — OEM specification
• O-rings / seals for pump fittings × 1 — OEM specification — replace any disturbed seal

Fluids

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

Preparation

1. Park on level ground, place transmission in neutral or P (early Roadsters are manual — leave in 1st gear), and engage the parking brake.
2. Exit all doors with the key fob at least 10 feet from the vehicle. Wait a minimum of 2 minutes for HV systems to de-energize, even on this non-HV-direct job.
3. Disconnect the 12V auxiliary low-voltage battery (located in the Roadster's front trunk area — refer to Roadster service documentation for exact location). Negative terminal first.
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. Confirm Tesla Toolbox (Roadster-compatible version) is connected and the battery cooling loop has been commanded to depressurize per Toolbox workflow. Do not proceed otherwise.
7. Allow the vehicle to sit until coolant is at ambient temperature — the Roadster ESS loop can hold residual heat and pressure for a long time.
8. Raise and support the vehicle on its specified jacking points. The Roadster's bonded aluminum tub will deform if loaded incorrectly.
9. Position a coolant catch pan of at least 12 qt capacity beneath the pump area.
10. Identify the coolant pump location for the loop being serviced (the Roadster has multiple pumps across the ESS, PEM, and motor cooling circuits — confirm which pump is being replaced before disturbing any line).

Procedure

1. 1

   Verify loop depressurization
   With Tesla Toolbox connected, confirm the relevant coolant loop has been depressurized and that no HV interlocks are active. Visually confirm no orange HV cabling runs through the immediate work area before proceeding. Do not loosen any fitting until depressurization is confirmed.
   ⚠️Skipping Toolbox depressurization can spray hot coolant onto HV battery components, causing immediate HV battery damage (~$15,000+) and risk of short or fire.
2. 2

   Access the coolant pump
   Remove any underbody panels, splash shields, or covers required to expose the pump. Note clip and fastener locations. The Roadster uses a mix of plastic clips and small machine screws — do not over-torque on reinstall.
   Torque spec

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

   Identify and label coolant hoses
   Photograph and label the inlet and outlet hoses to the pump. Note hose routing relative to surrounding components, especially any orange HV cabling, which must NOT be disturbed.
   ⚠️Reversed hose routing on a Roadster shared loop can cause the HV battery to overheat or freeze locally, leading to cell damage and possible thermal runaway.
4. 4

   Disconnect electrical connector to pump
   Release the low-voltage connector to the coolant pump. The connector is low-voltage (12V) but route it away from the work area. If a connector retainer bolt is present, remove it carefully.
   Torque spec

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

   Drain coolant from the loop
   Position the catch pan. Loosen the lower hose clamp on the pump first to allow controlled drainage. Capture all coolant — Tesla Battery/Motor Coolant (G-48) must be disposed of as hazardous waste and never mixed with standard automotive coolant.
   ⚠️Open coolant lines can allow fluid to migrate to HV battery interfaces. Catch ALL coolant; any drip onto the ESS enclosure or HV connectors must be cleaned and inspected before re-energizing the vehicle. Improper handling can damage the HV battery (~$15,000+ to replace).
   Torque spec

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

   Disconnect coolant hoses from the pump
   With the loop drained, remove both hose clamps and carefully work the hoses off the pump barbs. If hoses are stuck, use a hose-removal pick — do not pry against any HV component or aluminum chassis member.
   ⚠️Breaking the loop exposes the shared battery cooling circuit. Coolant contact with HV components can damage the HV battery (~$15,000+) and create electrical hazards. Keep the area clean and contained.
   Torque spec

   Hose Clamps3 Nm (2 lb-ft)

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

   Remove pump mounting hardware
   Remove the bolts securing the pump to its bracket (or the bracket to the chassis, depending on configuration). Support the pump as the last fastener is removed.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)

   Bracket Bolts20 Nm (15 lb-ft)
8. 8

   Remove old pump
   Withdraw the pump from the vehicle. Inspect the bracket and isolators for damage; replace any cracked rubber isolators. Compare the old pump to the new one to confirm correct part before installing.
   ⚠If the new pump does not match the removed unit (port size, electrical connector, mounting pattern), STOP. Roadster pumps vary by loop and supplier batch — installing the wrong pump can cause inadequate flow to the HV battery.
9. 9

   Install new coolant pump
   Position the new pump and install mounting hardware finger-tight, then torque to specification. Ensure the pump is oriented correctly — flow direction arrows on the pump body must match the loop direction.
   ⚠️Incorrect flow direction will starve the HV battery of cooling and can cause permanent battery damage (~$15,000+ to replace). Verify the arrow on the pump matches loop flow.
   Torque spec

   Mounting Bolts27 Nm (20 lb-ft)

   Bracket Bolts20 Nm (15 lb-ft)
10. 10

    Reconnect coolant hoses
    Install hoses onto the pump barbs. Use new hose clamps if the originals are single-use spring clamps. Ensure clamps are positioned past the barb bead and torque (worm-drive style) to specification.
    ⚠️A loose hose connection can dump coolant onto the HV battery enclosure under load, causing potential short and battery damage (~$15,000+).
    Torque spec

    Hose Clamps3 Nm (2 lb-ft)

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

    Reconnect electrical connector
    Reconnect the pump's low-voltage connector. Confirm the latch fully engages. If a retainer bolt is present, install and torque it.
    Torque spec

    Connector Bolts7 Nm (5 lb-ft)
12. 12

    Refill and bleed coolant loop
    Using a vacuum fill tool where possible, refill the loop with Tesla Battery/Motor Coolant (G-48 specification). Total system capacity is approximately 10 quarts but the actual fill quantity depends on how much was retained elsewhere in the loop. Follow the Toolbox-driven bleed procedure — manual bleeding is not sufficient on the Roadster's shared HV loop.
    ⚠️Air pockets in the shared loop can cause localized HV battery overheating without a coolant temperature warning. The Toolbox-driven bleed and pump-cycle routine MUST be completed; failure can damage the HV battery (~$15,000+).
13. 13

    Reinstall covers and shields
    Reinstall any underbody panels, covers, and clips removed for access. Verify no tools or rags remain in the engine bay/rear sub-frame area.
    Torque spec

    Cover Screws11 Nm (8 lb-ft)

Reassembly

1. Reconnect the 12V low-voltage battery (positive first, then negative).
2. With Toolbox still connected, command the cooling pump on and monitor flow, current draw, and temperature sensors across the ESS, PEM, and motor loops.
3. Run the Toolbox-prescribed bleed cycle until no air is detected and coolant level stabilizes.
4. Top off the coolant reservoir to the cold-fill mark with Tesla-spec G-48 coolant.
5. Inspect all disturbed fittings for leaks under pump operation.

Verification

• With Toolbox, confirm no DTCs related to ESS thermal management, pump current, or coolant temperature.
• Verify pump audible operation and correct current draw per Toolbox live data.
• Run the vehicle through a short drive cycle and recheck for leaks at every disturbed connection. Pay particular attention to any drip path that could reach the ESS enclosure.
• Recheck coolant level after the system has cycled hot/cold once and top off as needed.
• Document service date and mileage — Tesla now recommends battery coolant inspection at 4 years / 50,000 miles, so record this as the new baseline.
• If any coolant contacted HV connectors or the ESS enclosure during the job, do NOT return the vehicle to service until a Tesla-certified technician has inspected and isolation-tested the HV system.

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