Coolant Pump – 1.5 Series

Tesla Roadster 1.5 — ESS Pack Coolant Pump (12 V Bosch-type, Replacement Unit)

The Roadster 1.5 ESS (Energy Storage System) main battery relies on a dedicated 12 VDC electric coolant pump to move a water/propylene-glycol mix through the pack and front heat-exchanger loop. Proper flow keeps cell temperatures balanced, protects pack life, and prevents thermal derate or shutdown.

Why these pumps fail

• Brush/commutator wear — Normal DC motor wear reduces torque/flow and creates intermittent operation.
• Bearing drag — Age/heat dry lubrication, increasing current draw and lowering RPM.
• Impeller fouling or cavitation — Debris/aeration lowers head pressure and flow.
• Coolant contamination — Incorrect or aged coolant can corrode internals and shorten seal life.

The typical end state is reduced or zero flow, elevated ESS temperature, thermal derate, and potential vehicle shutdown to protect the pack.

Our solution

• Direct-fit replacement — Bosch-type 12 V pump with correct hose clocking and mounting for the Roadster 1.5 ESS loop.
• New motor/brushes & seals — Restores pressure and flow; reduces current draw versus tired units.
• Service interval — Proactive replacement every 5–7 years (or at the first signs of noise or intermittency) to protect the ESS.

Included in ESS service

Pump inspection/replacement is a standard reliability item during our Roadster battery/ESS service and thermal-system refresh.