Coolant Leakage Through a Cylinder-Head Exhaust Port Caused by Shrinkage Porosity
An engine cylinder head failed after operating just 3.2 km (2 mi) because of coolant leakage through the exhaust port. Visual examination of the exhaust ports revealed a casting defect on the No. 7 exhaust-port wall. A 0.9x examination of an unpolished, unetched longitudinal section through the defect indicated shrinkage porosity. This defect was found to interconnect the water jacket and the exhaust gas flow chamber. No cracks were found by magnetic-particle inspection. The gray iron cylinder head had a hardness of 229 HRB on the surface of the bottom deck. The microstructure consisted of type A size 4...
Coolant Leakage Through a Cylinder-Head Exhaust Port Caused by Shrinkage Porosity, ASM Failure Analysis Case Histories: Automobiles and Trucks, ASM International, 2019, https://doi.org/10.31399/asm.fach.auto.c0047263
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