Improved Cylinder Head Casting for 1997-2012 Cummins 15.0L
ISX & QSX Engines
- Increased top deck thickness
- Increased thickness of the wall above the exhaust ports
- Introduction of gussets between the bolt boss and the guide boss.
Top deck cracks in the old cylinder head were occurring at the center cup plug on the spring deck allowing coolant to mix with the oil.
Exhaust port cracks in the old cylinder head were occurring at the guide boss area of the port allowing coolant to leak into the exhaust port and showing up as a loss of coolant.
Old and New Signature/ISX/QSX15 Cylinder Head Part Numbers
Part Description Old Part Number New Part Number
ISX Cylinder Head 3683986 4962732