Cummins Plain Coolant Hose 4078469

Cummins Plain Coolant Hose 4078469

Note: Full hose dimensions, confirmed serial-number fitment ranges, and any supersession history for Cummins 4078469 should be verified against the current Cummins QuickServe parts catalog or a Cummins dealer lookup for your specific engine model and serial number. The application information below reflects commonly documented usage for this part number and should be confirmed before ordering.

What This Part Is

Cummins 4078469 is a genuine OEM plain (unlined) coolant hose for use in the engine cooling system circuit. Cummins designates “plain” hoses as those without an internal reinforcement lining, used in cooling-system routing positions where the hose connects coolant passages between the engine block, thermostat housing, water pump, or associated cooling-circuit components. Maintaining intact, leak-free coolant hoses is critical to engine temperature regulation and preventing overheating on heavy-duty diesel engines.

Compatible Applications

• Cummins ISX15 diesel engines — cooling system (confirm position and serial number)
• Cummins QSX15 diesel engines — cooling system (confirm position and serial number)
• Other Cummins heavy-duty diesel applications where 4078469 is listed (confirm by engine serial number via Cummins QuickServe)

Hose routing positions and part numbers vary by engine configuration, emissions tier, and serial range within the same engine family. Always confirm against your engine serial number before ordering.

Fitment Notice

Locate the engine data plate and record the full engine model designation and serial number before ordering. Confirm part number 4078469 is listed for your specific engine configuration using the Cummins QuickServe Online parts catalog or a Cummins dealer. If you have your engine serial number, contact us and we can assist with confirmation.

When to Replace

• Hose is cracked, hardened, collapsed, swollen, or shows surface checking
• Coolant leakage or seepage is visible at the hose or clamp connections
• Hose feels soft, mushy, or excessively stiff when squeezed cold
• Clamp area shows corrosion, erosion, or hose wall thinning
• Hose interior shows delamination or contamination when removed
• Hose has reached the age or service interval specified in the Cummins maintenance schedule
• Any time the cooling system is opened for water pump, thermostat, or block service

Installation Notes

• Confirm part number 4078469 is correct for the specific cooling-system position on your engine before installation
• Drain and recover coolant before removing the hose — follow Cummins coolant handling and disposal procedures
• Clean the mating spigots and check for corrosion or erosion that could affect the seal
• Inspect the hose clamps and replace any that are corroded, damaged, or undersized
• Route the new hose clear of hot exhaust components, sharp edges, and moving parts
• Refill with the correct Cummins-specified coolant type and concentration — do not mix coolant types
• Run the engine to operating temperature and check for leaks at all hose connections after service

Service Interval

Inspect coolant hoses at each scheduled cooling system service and at annual preventive maintenance. Cummins recommends inspecting all hoses for cracking, collapse, swelling, and clamp condition at each major service interval. Replace hoses proactively if there is any doubt about their condition — a failed coolant hose on a heavy-duty diesel engine can cause rapid overheating and significant engine damage.

Technical FAQ

What does “plain hose” mean in Cummins terminology?
Cummins uses “plain” to describe hoses without an internal fabric or wire reinforcement lining. These are used in cooling-circuit positions where the hose does not need to resist high internal vacuum or external abrasion. The opposite designation is typically “reinforced” or “flex” hose, used in positions subject to higher stress or movement.

How do I find the correct hose position for my engine?
Use the Cummins QuickServe Online parts catalog (quickserve.cummins.com) with your engine serial number. The cooling system hose diagram will show each hose position with its corresponding part number. Confirm that 4078469 is listed for your specific position and serial range before ordering.

Can I use an aftermarket hose as a substitute?
Aftermarket coolant hoses in the correct dimensions may be available, but Cummins OEM hoses are specified to match the exact routing geometry, ID, OD, bend angles, and material specification for each position. For heavy-duty commercial and marine diesel applications, OEM hoses are the lowest-risk choice.

What coolant should I use when refilling after hose replacement?
Use the coolant type and concentration specified in the Cummins Operation and Maintenance Manual for your engine — typically Cummins Fleetguard ES Compleat or equivalent pre-approved coolant. Do not mix OAT, HOAT, and conventional coolant types.

Parts Desk Insights

The most important step with any Cummins hose order is confirming the exact routing position using the engine serial number in QuickServe — the same engine family can have multiple plain hoses at different positions with different part numbers, and a wrong hose may not fit the spigot or routing geometry even if it looks similar. At this price point, a wrong-fitment return is not trivial. If the customer has the serial number and can identify the diagram position, the order is straightforward. If they only have the engine model, it’s worth the extra confirmation step before shipping.