TSB220220

Front Face Cup Plug Missing from Cylinder Head
Page 1 of 3
Technical Service Bulletin
Technical Service Bulletin:
Released Date: 14-Apr-2023
TSB220220
Front Face Cup Plug Missing from Cylinder Head
Front Face Cup Plug Missing from Cylinder
Head
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.
Contents
Product Affected
•
•
•
•
•
•
•
B6.7 CM2350 B121B
B6.7 CM2450 B155B
ISB6.7 CM2350 B101
ISL CM2350 L101
L9 CM2350 L116B
L9 CM2350 L123B
L9 CM2450 L126B
Issue Summary
Symptom:
• Cup plugs missing from the fuel drain line at the front face of the cylinder head
• External fuel leak
Root Cause:
• Debris plugging the fuel drain line at the rear of the cylinder head causing excessive
fuel drain line restriction and resulting in cup plug dislodging.
• Analysis has consistently shown urea in these deposits, indicating diesel exhaust
fluid (DEF) in fuel tank.
https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2022/tsb220220.html
4/18/2023
Front Face Cup Plug Missing from Cylinder Head
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Verification
• Inspect the fuel drain line on the cylinder head for debris. See Figure 1.
• Debris present in the fuel drain line contains urea/DEF.
Figure 1, Example View of Fuel Return Line Clogged with DEF Debris.
Resolution
• Reference Service Bulletin, Diesel Fuel Contaminated with Water, Gasoline, or
Diesel Exhaust Fluid (DEF), Bulletin 5659823.
• Remove check valve fitting from the rear of the cylinder head and look for debris in
the drilling. If found, remove the number 6 injector and clean out the debris.
• Run a flexible brush through the fuel drain line, the high-pressure fuel line, and the
injector bore to clean out all the debris. Use contact cleaner as needed.
Document History
Date
2022-10-27
Details
Module Created
https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2022/tsb220220.html
4/18/2023
Front Face Cup Plug Missing from Cylinder Head
Date
2023-4-13
Page 3 of 3
Details
Updated Symptom section to include external fuel leak.
Last Modified: 14-Apr-2023
https://quickserve.cummins.com/qs3/pubsys2/xml/en/tsb/2022/tsb220220.html
4/18/2023