3974823 5292708 Thermostat for Cummins 180℉ 5.9L ISB 4.5L QSB Engines

Product Overview

This aftermarket replacement thermostat is intended for Cummins 5.9L ISB, 4.5L QSB, and B-Series engine applications and cross-references part numbers 3974823 and 5292708. A thermostat regulates coolant flow through an engine cooling system to support normal temperature regulation.

Key Features & Performance

• Regulates coolant flow as part of the engine cooling system.
• Specified for the listed Cummins engine applications.
• Cross-references part numbers 3974823 and 5292708.
• Suitable for servicing or replacing the corresponding thermostat.

Fitment & Compatibility

• for Cummins 5.9L ISB engine applications
• for Cummins 4.5L QSB engine applications
• for Cummins B-Series engine applications

Common Uses

• Replacing a worn, damaged, or malfunctioning engine thermostat.
• Routine maintenance of the engine cooling system.
• Servicing the coolant flow control component associated with the engine.

Technical Specifications

• Product Type: Thermostat
• Temperature Rating: 180℉
• Part Number(s): 3974823, 5292708
• Engine Application(s): Cummins 5.9L ISB, 4.5L QSB, B-Series engines

Frequently Asked Questions

Q: What does this thermostat do? A: A thermostat regulates coolant flow through the engine cooling system to support normal operating temperature regulation.

Q: How should fitment be verified? A: Compare the complete part number, including 3974823 or 5292708, and the complete engine designation, such as 5.9L ISB, 4.5L QSB, or B-Series, with the existing component and equipment documentation.

This is an aftermarket replacement part and is not represented as genuine or original equipment. Product appearance and specifications may vary slightly by batch. Compatibility may vary by serial number, model year, or existing part number. Verify fitment before purchase.