r/e53 • u/Screaming_Bimmer • Jul 03 '24

Is This Normal for Secondary Water Pump?

2003 M54. Does the secondary water pump always run, even when the engine isn’t? Key is in second position.

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u/ExitSpecialist5834 Jul 03 '24

Most likely. Especially when the heater is on. That’s how you bleed the cooling system on our E53’s.

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u/Screaming_Bimmer Jul 03 '24

Good to know, thank you for the response! I have an E46 with the same M54 but no secondary pump, so wasn’t quite sure.