TSB150196-031620

3/25/2021
Natural Gas Leak into Engine Cooling System
Technical Service Bulletin
Technical Service Bulletin: TSB150196
Natural Gas Leak into Engine Cooling System
Released Date: 16-Mar-2021
Natural Gas Leak into Engine Cooling System
Warranty Statement
The information in this document has no effect on present warranty coverage or repair practices, nor does it authorize TRP or
Campaign actions.
Information Only - OEM Related Matter Not Covered By Cummins® - Contact Appropriate OEM Dealer or OEM Representative For
Additional Information
Contents
Product Affected
B Gas International CM556
B Gas Plus CM556
B Gas Plus CM556
B5.9G
C Gas Plus
C Gas Plus CM556
C8.3G
ISB5.9 G CM2180
ISC8.3 G CM2180 C101
ISL G CM2180 EJ
ISX12 G CM2180 EJ
L Gas Plus CM556
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Natural Gas Leak into Engine Cooling System
L10 Gas
L9N CM2380 L124B
L9N CM2380 L130B
L9N CM2380 L142B
Issue
Many compressed natural gas (CNG) and liquefied natural gas (LNG) fuel systems use engine coolant to warm the natural gas high
pressure regulator and/or heat exchanger. A leaking original equipment manufacturer (OEM) high pressure fuel system component
can cause natural gas to leak into the engine cooling system. This natural gas leak forces coolant out the coolant reservoir.
Verification
 WARNING 
If natural gas leaks are present, do not store the vehicle inside or in any area that is covered. Severe personal injury can
result from asphyxiation or explosion.
 WARNING 
Natural gas is explosive and flammable. Always be sure to maintain adequate ventilation in the work area. Keep all
cigarettes, flames, pilot lights, arcing equipment, and switches out of the work area and areas with shared ventilation to
reduce the possibility of severe personal injury or death when working on a natural gas system.
 WARNING 
Natural gas is lighter than air. Check the ceiling of the area where work is to be done for any possible ignition source.
 WARNING 
Always have proper ventilation when working on a natural gas system
When diagnosing external coolant loss:
Visually check to see if bubbles are present with the engine off and high pressure fuel valve on.
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Natural Gas Leak into Engine Cooling System
If bubbles are observed, the high pressure fuel system must be tested for leaks. See the Resolution section below.
Resolution
Troubleshoot the high pressure fuel system components. See equipment manufacturer service information or OEM fuel system
supplier instructions.
Fuel system provider customer service contact numbers*:
Agility® Fuels Systems +1-949-267-7745
Trilogy Arctic Fox® Inline CNG fuel heater +1-330-915-2303 extension 109
Quantum Technologies + 1-800-816-8691
Chart® Industries + 1-888-877-3093
Note : *Contact information subject to change. This is not a complete list of fuel system providers.
Document History
Date
Details
2015-12-16
Module Created
2021-1-20
Added L9 engines.
2021-3-16
Update to Verification section.
Last Modified: 16-Mar-2021
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