ACDelco 252-845 Engine Water Pump

Part Number
Engine Water Pump

Fits: 99-06 Chevrolet Silverado 1500, 99-00 Chevrolet Silverado 2500, 99-06 GMC Sierra 1500, 99-00 GMC Sierra 2500, 02 Chevrolet Silverado 2500, 00-06 Chevrolet Suburban 1500, 00-06 Chevrolet Tahoe, 02 GMC Sierra 2500, 00-06 GMC Yukon, 00-06 GMC Yukon XL 1500, 02-06 Cadillac Escalade, 02-06 Cadillac Escalade EXT, 02-06 Chevrolet Avalanche 1500, 02-05 Chevrolet Silverado 2500 HD, 02-05 GMC Sierra 2500 HD, 03-06 Cadillac Escalade ESV, 03-06 Chevrolet Express 1500, 03-06 Chevrolet Express 2500, 03-06 Chevrolet Express 3500, 03-06 Chevrolet SSR, 03-06 Chevrolet Trailblazer EXT, 03-06 GMC Envoy XL, 03-06 GMC Savana 1500, 03-06 GMC Savana 2500, 03-06 GMC Savana 3500, 03-05 Isuzu Ascender, 04-06 Buick Rainier, 04-05 Chevrolet Silverado 3500, 04-05 GMC Envoy XUV, 04-05 GMC Sierra 3500, 04 Hummer H2, 05-06 GMC Envoy, 05-06 Saab 9-7x, 06 Chevrolet Trailblazer

Special Price $119.84 Regular Price $140.99
In stock
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Estimated Ship Date: 1 Business Day or Less
An ACDelco Professional, premium aftermarket Engine Water Pump circulates coolant through your vehicle's radiator and engine system to help maintain proper engine temperature and performance. The gaskets, seals, and O-rings packaged with this Professional, premium aftermarket water pump help guarantee that all necessary parts are available for trouble-free installation. ACDelco Professional Water Pumps are a high quality replacement for many vehicles on the road today. This premium aftermarket replacement engine water pump is manufactured to meet your expectations for fit, form, and function. ? WARNING: Cancer and Reproductive Harm -



  • All Makes water pumps fit GM vehicles as well as a wide range of non-GM vehicles
  • Buick;Cadillac;Chevrolet;GMC;Hummer;Isuzu;Saab
  • Cast-iron or aluminum design, depending on vehicle application
  • Coated seals support seal longevity and durability
  • Come with premium, high-quality replacement components needed for trouble-free and accurate installation
  • Heat-treated shaft assemblies provide superior strength and durability over non-treated assemblies
  • High-quality bearings are permanently sealed and lubricated for greater durability and long life
  • Thoroughly tested for reliable, leak-free performance
  • Uniform wall sections and smooth coolant-flow cavities for efficient operation


Casting Number18-1652
Fan Clutch IncludedNo
FAQ - Answer 1Yes. ACDelco Professional Water Pump Kits and Water Pumps are for both GM and non-GM vehicle applications.
FAQ - Answer 2Yes. ACDelco Professional Water Pump Kits and Water Pumps are packaged with the gaskets, seals, and O-rings needed for installation.
FAQ - Answer 3No. Water pumps can vary greatly in size and appearance depending on the vehicle they are designed for.
FAQ - Answer 4Yes. The water pump is responsible for moving coolant through your vehicle's cooling system, keeping the heat generated by your engine at acceptable levels, and helping prevent overheating. A malfunctioning water pump can cause your engine to overheat, which may result in severe and costly engine damage.
FAQ - Answer 5Yes. As part of regular cooling system operation, the water pump sends hot coolant to the heater core of your engine, which transfers heat into the passenger cabin of your vehicle. If this hot coolant is unable to reach the heater core, then this heat transfer cannot occur, and your passenger compartment remains colder than you want.
FAQ - Answer 6No. Your vehicle's water pump keeps coolant moving as long as the engine is running, and stops when the engine is turned off. If you want to be able to circulate coolant for a short time after the engine has been turned off, an auxiliary electric water pump is needed.
FAQ - Question 1Can I use ACDelco Professional Water Pump Kits and Water Pumps on my non-GM vehicle?
FAQ - Question 2Do ACDelco Professional Water Pump Kits and Water Pumps come with installation components?
FAQ - Question 3Do all water pumps look the same?
FAQ - Question 4Can a malfunctioning water pump harm my engine?
FAQ - Question 5Does the water pump affect the temperature inside the passenger compartment of my vehicle?
FAQ - Question 6Does the water pump work when my vehicle is turned off?
Good Maintenance Practices - Section 1 - Bullet 1Clean all excess dirt and debris from the water pump housing.
Good Maintenance Practices - Section 1 - Bullet 2Run your vehicle to increase engine temperature, and ensure the system is pressurized.
Good Maintenance Practices - Section 1 - Bullet 3Inspect for leakage at the water pump outlet housing or the rear cover gasket, and leakage at the water pump vent or weep hole.
Good Maintenance Practices - Section 1 - Bullet 4A stain around the weep hole is acceptable. However, if a weep occurs with the engine running and the coolant system pressurized, then the water pump should be replaced.
Good Maintenance Practices - Section 1 - HeaderTips for Water Pump Inspection:
Good Maintenance Practices - Section 2 - Bullet 1Determine the root cause of failure, particularly if the water pump failed prematurely.
Good Maintenance Practices - Section 2 - Bullet 10After installation, pressure-test the system for leaks and check for sufficient fan blade clearance between the blade and radiator shroud.
Good Maintenance Practices - Section 2 - Bullet 11Inspect related components in the cooling system, including your fan blades, fan clutch, engine mounts, radiator, belts and hoses, and reservoir.
Good Maintenance Practices - Section 2 - Bullet 2Clean and reinstall the coolant recovery reservoir before flushing the cooling system.
Good Maintenance Practices - Section 2 - Bullet 3Flush the cooling system completely, using power flush equipment or thermal cycling the system with clean water three times. The most effective method of system flushing is to use a coolant exchanger, following the manufacturer's operating instructions.
Good Maintenance Practices - Section 2 - Bullet 4Do not use any non-approved flush agents, and replace the coolant according to manufacturer's specifications.
Good Maintenance Practices - Section 2 - Bullet 5Clean all sealing surfaces, and make sure all old gasket material is removed before installing your replacement component.
Good Maintenance Practices - Section 2 - Bullet 6Never strike the water pump shaft, since this will damage the new water pump.
Good Maintenance Practices - Section 2 - Bullet 7Torque all bolts according to the manufacturer's specifications, and adjust belts to proper tension (if applicable) to manufacturer's specifications.
Good Maintenance Practices - Section 2 - Bullet 8Use sealant tabs only if recommended. Some sealant tabs or similar compounds may restrict coolant flow through the passages of some cooling systems.
Good Maintenance Practices - Section 2 - Bullet 9With the new water pump installed, turn the hub by hand and check for rotation.
Good Maintenance Practices - Section 2 - HeaderTips for Water Pump Servicing & Installation:
Good Maintenance Practices - Section 3 - Bullet 1Flush your cooling system whenever the water pump or other system components are replaced. This will help prevent contamination from entering the system, which may result in repeated failure.
Good Maintenance Practices - Section 3 - Bullet 2Utilize quality coolant when refilling your cooling system with the recommended 50/50 coolant/water mix. Distilled water should be used, as hard tap water can leave mineral deposits in the cooling system and reduce coolant flow, or result in corrosion and seal damage. Contaminated or depleted coolant can also result in corrosion and seal damage, and lead to pump failure. Take care to select the correct coolant for your vehicle by consulting the vehicle manufacturer's service information.
Good Maintenance Practices - Section 3 - Bullet 3Never overtighten your drive belts. Belts that are too tight may cause an overload on pump bearings, greatly reducing the life of the water pump.
Good Maintenance Practices - Section 3 - Bullet 4Inspect the fan blade. If damage is not detected, bent blades, loose rivets, and cracks may result in premature bearing failure. If damage is found, do not try to repair the fan-the part should be replaced.
Good Maintenance Practices - Section 3 - Bullet 5Ensure that your engine fan pulley (or clutch, if used) is seated properly on the pump's shaft. If the fan wobbles during rotation, vibration resulting in premature bearing wear may occur. Also check the fan clutch for wear and replace as necessary.
Good Maintenance Practices - Section 3 - Bullet 6Inspect the thermostat and radiator cap. Examine your thermostat and radiator cap, and replace if they show signs of sticking or leaking.
Good Maintenance Practices - Section 3 - HeaderTips to Help Prevent Water Pump Failure:
Height (in)9.1
Housing MaterialAluminum
Hub Hole Quantity0
Impeller MaterialSteel
Impeller RotationReverse
Impeller Vane Quantity7
Includes Back HousingNo
Informational Chart 1PL25_PL26_IC_WaterPumpComposition.jpg
Informational Chart 2PL25_PL26_IC_CoolingSystemOperation.jpg
Installation WarningsYes
Length (in)18.3
Mounting Hardware IncludedNo
Mounting Hole Quantity6
Outlet Quantity4
Programming RequiredNo
Pulley IncludedYes
Pulley Outside Diameter (in)5.843
Signs of Wear & Troubleshooting - Section 1 - Bullet 4Visible Component Wear - Worn seals, corrosion, cavitation/pitting of pump components, or a loose or wobbly pump shaft are all signs of wear that may lead to pump failure, and should be addressed.
Thermostat And Housing IncludedNo
Water Pump Drive TypeSerpentine Belt
Weight (lb)13.1
Width (in)12.3



  • 1999-2000 Chevrolet Silverado 2500
  • 2000-2006 GMC Yukon XL 1500
  • 2003-2006 Cadillac Escalade ESV
  • 2003-2005 Isuzu Ascender
  • 2002-2005 Chevrolet Silverado 2500 HD
  • 2002-2002 GMC Sierra 2500
  • 2005-2006 GMC Envoy
  • 2003-2006 Chevrolet Express 3500
  • 2003-2006 Chevrolet SSR
  • 2005-2006 Saab 9-7x
  • 1999-2006 Chevrolet Silverado 1500
  • 2002-2005 GMC Sierra 2500 HD
  • 2002-2006 Cadillac Escalade EXT
  • 2003-2006 Chevrolet Trailblazer EXT
  • 2004-2005 Chevrolet Silverado 3500
  • 2004-2005 GMC Envoy XUV
  • 2003-2006 GMC Savana 3500
  • 2004-2006 Buick Rainier
  • 2000-2006 Chevrolet Suburban 1500
  • 2004-2004 Hummer H2
  • 2003-2006 GMC Envoy XL
  • 1999-2000 GMC Sierra 2500
  • 2000-2006 GMC Yukon
  • 2002-2006 Cadillac Escalade
  • 2000-2006 Chevrolet Tahoe
  • 2003-2006 Chevrolet Express 2500
  • 2002-2002 Chevrolet Silverado 2500
  • 1999-2006 GMC Sierra 1500
  • 2004-2005 GMC Sierra 3500
  • 2003-2006 GMC Savana 1500
  • 2003-2006 GMC Savana 2500
  • 2003-2006 Chevrolet Express 1500
  • 2002-2006 Chevrolet Avalanche 1500
  • 2006-2006 Chevrolet Trailblazer
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