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Cummins 3.9L / 5.9L Water Pump 1989-2010 | Bostech WP03300


Bostech's line of new heavy-duty water pumps are backed by our 24-month unlimited mileage warranty. We offer 50 plus skus covering most diesel engine applications. Our pumps are quality engineered according to the OEM's design and assembled with high-performance bearings, durable long-lasting seals, and for most applications upgraded impellers. Top-quality product direct from a Trusted Manufacturer - Bostech!


  • Cummins 3.9L B-Series
  • Cummins 5.9L ISB

Technical Information:

  • Housing Material: Cast Iron
  • Impeller Material: Steel
  • Impeller Vanes: Shielded 5 Vanes
  • Pulley Style: Smooth with slant top
  • Pulley Diameter: 3.464 in / 88mm
  • Mounting: 2 Bolt

Note: There are 3 Cummins 5.9L Water Pumps which look identical with the exception of the impeller, please verify:

  • WP03300 - Steel Impeller with 5 shielded vanes
  • WP03302 - Cast Iron Impeller with 7 vanes
  • WP04278 - Steel Impeller with 5 open vanes
Housing Material:
Cast Iron
Impeller Material:
Impeller Style:
Shielded 5-Vanes
Pully Diameter:
3.464 inches / 88mm
Prop65 Warning:
WARNING: Cancer and Reproductive Harm -
Bostech / BT-Power's 24-Month Unlimited Mileage Warranty. Our warranty covers product replacement for material and/or workmanship defects up to 24-months from the product purchase date. Technical Support is available by contacting Bostech's Customer Service at 1-800-868-0057 or by emailing An RMA (Return Material Authorization) number given by Customer Service is required for all returns. You can view our Warranty Policy by clicking the "Help Center" at the bottom of the page and going to Policies & Procedures.