Reference and Interchange Numbers
- A-Premium APWP0321
- ACDelco 252-845
- GM 19195104
- GM 89018166
- Airtex AW5104
- Gates 45006
- GMB 130-7340AT
- US Motor Works US64-T
- CP5104
- DP998
- WP-9106
- WP-9409
The A-Premium product listing identifies this kit as APWP0321, while the official GM parts catalog lists 19195104 as ACDelco 252-845.
Product Specifications
| Specification | Details |
|---|---|
| Pump type | Mechanical engine water pump |
| Drive system | Serpentine belt |
| Housing material | Aluminum |
| Impeller material | Metal |
| Impeller rotation | Reverse |
| Hub pilot diameter | Approximately 5.85 inches |
| Hub height | Approximately 6.57 inches |
| Thermostat | Included |
| Gaskets | Included |
| Warranty | One year, unlimited mileage |
The original description incorrectly calls 5.85 inches the hub diameter. Published specifications for the matching GMB 130-7340AT identify it as the hub pilot diameter, with a hub height of approximately 6.57 inches.
What the Kit Includes
- One assembled mechanical water pump
- One thermostat
- Water-pump gaskets
- Required seals as supplied by the manufacturer
Check the package before disassembly. Replacement bolts, coolant, hoses, clamps and specialty tools are not necessarily included.
Why Replace the Water Pump and Thermostat Together?
A worn water pump can develop bearing noise, shaft play, seal leakage or reduced coolant flow. A sticking thermostat can create many of the same overheating complaints. Replacing both components while the cooling system is drained reduces duplicated labor and removes two common failure points at once.
Our bad thermostat versus bad water pump guide explains how to separate their symptoms before ordering parts.
Common Symptoms of Water-Pump Failure
- Coolant leaking near the front of the engine
- Dried coolant residue around the pump or weep hole
- Grinding or growling bearing noise
- Water-pump pulley wobble
- Engine overheating
- Poor coolant circulation
- Repeated coolant loss
- Belt misalignment or abnormal belt wear
- Cabin heat that becomes cold while the engine overheats
Overheating does not prove the pump is defective. Low coolant, trapped air, radiator restriction, a failed fan or combustion-gas leakage can produce similar symptoms.
Use our coolant-leak diagnostic guide before replacing components based entirely on one suspicious puddle.
Installation Recommendations
- Allow the engine to cool completely.
- Disconnect the negative battery cable.
- Drain the coolant into a suitable container.
- Remove the intake duct, fan assembly and belt as required.
- Inspect the fan clutch, tensioner, idlers and belt.
- Clean the engine’s gasket surfaces without gouging the aluminum.
- Install the supplied gaskets in the correct orientation.
- Torque the pump and thermostat-housing fasteners to GM specifications.
- Refill with the correct coolant mixture.
- Bleed the system and inspect for leakage.
- Confirm stable operating temperature during a road test.
Never open a hot pressurized cooling system. Hot coolant does a remarkable job of turning a routine repair into an emergency-room review.
If the old coolant is contaminated, follow our cooling-system flush guide. Use the correct coolant specification rather than choosing antifreeze by color; our coolant-type guide explains why.
Frequently Asked Questions
Does AW5104 fit all Chevrolet Silverado models from 1999–2006?
No. Fitment depends on the engine, model designation and production configuration. It is intended for specified 4.8L, 5.3L and 6.0L V8 applications—not every Silverado produced during those years.
Does this water pump fit a 5.7L Vortec engine?
No. The listed applications use Gen III 4.8L, 5.3L and 6.0L V8 engines. It is not intended for the earlier 5.7L small-block Vortec.
Does it fit an 8.1L big-block engine?
No. GM 8.1L V8 applications use a different water pump.
Is the thermostat included?
Yes. This A-Premium kit is advertised with a thermostat and installation gaskets.
Does it fit the 2007 Silverado Classic?
Some AW5104/252-845 catalogs show selected 2007 Classic applications, but this specific A-Premium listing stops at 2006. Verify the VIN and A-Premium catalog before expanding fitment.
Should the fan clutch be inspected?
Yes. A worn or unbalanced mechanical fan clutch can increase water-pump bearing load. Check it for leakage, excessive play and abnormal resistance while the assembly is accessible.
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