So my aux. water pump for awhile was starting/stoping during it's run cycle. Since then it has started/stopped in awhile, all seems good. Now that the outdoor temp. is dropping as it's that time of season .. the pump sometimes doesn't run at all, even after a short "spirited" drive it doesn't turn on...

My questions is, should the pump be coming on every single time the car is shut down? Or does it look for an extreme temperature in order to kick on? Also, if there were indeed something wrong with my pump, would it trigger a CEL?

Thank you in advance!

 

The auxiliary coolant pump is used to supplement the engine coolant pump to help with turbocharger cooling. It is mounted to the engine block, below the turbocharger. After the engine is shut off, the electric cooling fan may continue to run after the engine is shut off in two different scenarios. The system is operating as designed.

1. When the engine coolant temperature reaches 108 degrees Celsius (due to heat soak), the cooling fan will activate until the coolant temperature drops below 105 degrees Celsius. During this period, the fan has a maximum run time of 900 seconds (15 minutes) due to power management. Ambient or oil temperature has no effect on this run time.

2. On Cooper S vehicles with the N14 engine, the fan will run to assist the auxiliary water pump, which is used to cool the turbocharger after engine shut down. The maximum run time in this situation is 300 seconds (5 minutes).

When a coolant pump begins to fail, the check engine light will illuminate to warn you of the issue. Fault codes will be stored, which we list these fault codes in our Auxiliary Coolant Pump Replacement DIY, including this information above and more.

 

Ok, so that answers the CEL question, and if I'm reading this correctly, the Aux. pump will only cycle if the temp is 108 degrees celsius or higher, if the it's 105 degrees celsius for example, the pump need not run...