What is the Water Pump (Auxiliary) all about?

When most people hear the term “water pump”, their immediate thought is the pump that propels engine coolant through the engine, keeping it within optimum operating temperature. While that is certainly the most important one, there’s actually another pump on your car in some models and makes (not all cars have an auxiliary pump).

The auxiliary water regulates temperature on the car’s inside during cold days. It’s responsible for sending additional hot coolant through the car’s heater core, allowing you to work the heater (your car’s heater uses engine heat to warm the air that’s blown out of the vents). They were first used in the 1980s on diesel vehicles, but since then have seen adoption on gasoline engines as well.

Keep in mind:

• The auxiliary water pump is an electronic component, which, unlike the primary water pump that is activated by the drive belt, uses an electric motor to pump coolant.
• Over time, these pumps do wear out and will need to be replaced.

How it's done:

• The vehicle is raised and secured on jack stands and the coolant is drained
• The water pump hoses are disconnected and the pump is removed
• The new water pump is installed and the hoses are connected
• The coolant is filled and the water pump and hoses are checked for leaks
• The vehicle is removed from the jack stands and the engine is checked for proper operation. The vehicle is road tested for proper operation

Our recommendation:

Your best defense against a failed auxiliary water pump is to work with our expert mechanics that understand that these pumps are becoming more common, and can account for the pump’s presence when diagnosing heater problems. Note that auxiliary water pump failure will not affect the blower motor or the air conditioner operation – it only affects the production of heat, and these symptoms can range from creating mildly warm air to the heater blowing cold air.

What common symptoms indicate you may need to replace the Water Pump (Auxiliary)?

• Heater does not produce much warm air in stop-and-go traffic
• Heater does not release any warm air

How important is this service?

While replacing a failed auxiliary water pump is not critical for vehicle performance, it can be an inconvenience, particularly during the middle of winter if your heater can’t keep you warm. Your heater may also have trouble keeping your windows clear on humid and cold days. If you notice your car’s heater is not working properly, have it diagnosed by one of our expert mechanics.