What is the Cummins ISX12N?
ISX12N is a Cummins natural-gas engine designation. Cummins’ body-builder catalogue includes a 2018 listing, and the company distinguishes it from its later X15N natural-gas offering. It must not be confused with an ISX diesel or treated as a diesel engine with a different fuel-price label.
What matters in a comparison
For an ISX12N vehicle, establish the fuel-storage system, usable range and access to compatible refuelling on the intended route. Ask for documentation covering both the engine and the tanks. Natural gas can be billed using energy-equivalent measures, so litres and gallons of liquid fuel are not an appropriate substitute in this site’s trip-fuel calculator. Build a separate fuel-cost basis from the actual supplier quotation.
Fluids & filters
ISX12N natural-gas engine CM2380, Cummins QRG 5600484 revision 6/2025.
Reference checked:
Identify the unit first
Use these details to match the manufacturer's application record before choosing a fluid or ordering a filter.
- Truck VIN
- Engine model and serial number
- Engine emissions/model year
- Installed filter-housing model and original part number
- Factory coolant label and subsequent coolant-change records
Fluid specifications
Engine oil
Natural-gas engine oil meeting Cummins CES 20092; SAE 10W-30 or 15W-40.
ISX12N CM2380. Diesel oil viscosity or API category alone does not establish CES 20092 approval.
Source 1 ↗Engine coolant
Fully formulated SCA-precharged coolant meeting TMC RP 329 (ethylene glycol) or RP 330 (propylene glycol).
ISX12N CM2380 QRG; retain the installed coolant formulation or follow the OEM-approved changeover procedure.
Source 1 ↗Filter numbers & cross-references
A catalogue cross-reference links part numbers. It does not confirm that either part fits every version of this model. Match the original part to the unit first, then check the replacement manufacturer's application and any supersession.
Engine oil filter
Cummins publishes this pair for ISX12N CM2380. Verify the engine serial number and any current supersession before ordering.
Source 1 ↗Manufacturer catalogue cross-references
- Fleetguard LF14000NNCheck catalogue ↗
Crankcase ventilation filter
Cummins publishes this pair for ISX12N CM2380. Verify the engine serial number and any current supersession before ordering.
Source 1 ↗Manufacturer catalogue cross-references
- Fleetguard CV53009Check catalogue ↗
Optional natural-gas fuel filter
The ISX12N CM2380 table marks this fuel filter optional; first confirm that this assembly is installed. Verify the engine serial number and any current supersession before ordering.
Source 1 ↗Manufacturer catalogue cross-references
- Fleetguard NG5900Check catalogue ↗
Cummins parts catalog — identify the engine serial number ↗
Cummins QuickServe — serial-specific service information ↗
What still needs unit-specific confirmation
- Confirm current part supersessions and vehicle-specific fitment through the OEM before ordering. Quantities, capacities and maintenance intervals require the serial-specific manual.
Official service and parts references
Source 1 ↗ Source 2 ↗ Source 3 ↗Follow the current manufacturer's manual for the identified unit. This page does not set a drain interval, fill quantity or repair procedure.
Questions to take to the supplier
- Which gas-storage system is installed?
- What route-based refuelling access is available?
- Are engine and tank-system records both included?
Sources & limits
Manufacturer material supports the identification and overview above. Comparison considerations and supplier questions are Truck University’s original editorial interpretation, prepared with AI assistance. They are not an independent performance test or expert inspection.
Model-family reference only. Availability, specifications and service requirements can differ by year, market and configuration. Verify the actual vehicle or component using its identification and current manufacturer documentation. Do not use this page as a parts-fitment, modification, repair or loading instruction.
Published specifications and examples retain their labelled units; the header preferences apply to calculators.
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