Questions and Answers

Mercedes Benz Auxiliary Water Pump Q. My auxiliary water pump, the one for the climate control system, is going out. It makes a whining noise when the car is at idle or slow speeds and is also leaking a bit of coolant. I am about to order a new auxiliary water pump. However, while I am waiting for it to get here, is there anyway to disconnect the auxiliary water pump temporarily?

Will disconnecting this pump cause any problems? If it is possible to disconnect the pump for about a week without causing problems, how do I disconnect it?

• 1984 Mercedes Benz 380SL
• 121,000 miles

Ben
Clovis, New Mexico

A. The auxiliary water pump (30) serves to maintain a uniform coolant flow through the heat exchanger even at low engine speeds. During control operation, the pump is switched on by the signal "legroom flaps open". Electric activation is by way of the control unit.

If you want to disconnect the auxiliary water pump, just unplug it. If you want to bypass it, you can get a heater hose splice at a parts store and bypass the auxiliary water pump.