Originally Posted by Rydiak
Yes, this is true. Both units share the same reservoir.
Thanks Rydiak!
Are these pumps supposed to run continuously when the engine is running?
or
Are they thermostatically controlled by a temperature sensor?
Do they run for 5-20 seconds AFTER the engine is shut down like the C32/SLK32 AMG pumps supposedly do? Anyone with a known good pump (recently replaced) hear the pump run after engine shut down?

If so, we may have a simple diagnostic tool.