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Cadillac CTS STS 2008-2011 3.6L V6 Auxiliary Water Pump 25808860 251-721

Electric Auxiliary Coolant Pump for 2008–2011 Cadillac CTS/STS 3.6L – 25808860

SKU: NLT1Q01606
$41.99 In Stock
$41.99
Sale price  $41.99 Regular price 
Ships for free in 2–4 business days.
New aftermarket 12-volt auxiliary coolant circulation pump for compatible 2008–2009 Cadillac CTS and 2008–2011 Cadillac STS 3.6L V6 applications; replaces 25808860 and 251-721.
Estimated delivery between
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Compatible Models

We do our best to list all compatible models. Although this may be the part you need, your exact model may not appear below.

Compatible equipment / model
  • 2008–2009 Cadillac CTS 3.6L V6—matching auxiliary circuit
  • 2008–2011 Cadillac STS 3.6L V6

Product Overview

Poor heater output at idle, auxiliary-pump circuit faults, coolant seepage, or no pump operation can lead to this electric pump after coolant level, air pockets, wiring, fuse, and heater-core flow are checked. It circulates coolant through the supporting heater/cooling circuit when commanded.

The old description called it only a water pump, which can be confused with the engine-driven main pump. Match the electrical plug, hose ports, flow direction, and mounting.

Key Features & Performance

  • 12-volt electric auxiliary coolant pump
  • Supports heater/cooling circuit circulation
  • Cross-references 25808860 and 251-721
  • Separate from the engine-driven primary water pump

Replaces Part Numbers

  • 25808860
  • 251-721
  • 251721

Common Uses

  • Restoring auxiliary coolant flow
  • Replacing a leaking electric pump
  • Repairing a confirmed pump-circuit fault

Technical Specifications

  • Product Type: Electric auxiliary coolant pump
  • Voltage: 12V
  • Engine: 3.6L V6
  • Condition: New
  • Replacement Type: Aftermarket

Installation & Fitment

  • Work only on a cool, depressurized system
  • Clamp or drain coolant as the service procedure requires
  • Observe flow direction and secure hose clamps
  • Bleed air, restore coolant level, and command the pump with a scan tool if applicable

Compatibility Notice

Northline Parts does its best to list all known compatible models, but the correct part may fit an application not shown.

Model, engine, hose routing, connector, and production date affect fit. Match 25808860 and the removed auxiliary pump.

Frequently Asked Questions

Q: Is this the main engine water pump? A: No. It is an electric auxiliary circulation pump.

Q: Can air in the cooling system stop heater output? A: Yes. Bleed the system before assuming the pump is faulty.

Q: Does it fit every 2011 CTS? A: No. The verified CTS range here is 2008–2009; STS coverage extends through 2011.

Q: Can a scan tool test the pump? A: On supported vehicles, commanding the pump can help verify power and operation.

Part Summary

keywords: 25808860 auxiliary water pump, Cadillac CTS heater pump, STS 3.6 coolant circulation, 251-721 replacement, Cadillac poor heat at idle

Brand names, model numbers, and reference part numbers are used for identification and compatibility purposes only. Verify the original component, dimensions, and application before purchase.

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