John F. "Jack" Siewert, 86, of West Peoria, passed away at 9:25 p.m. on Monday, April 27, 2026, at OSF St. Francis Medical Center. He was born on March 24, 1940, in Peoria, to the late Herbert and Gertrude Siewert. He married Sheila Ann Epps on June 10, 1961. She survives.
Also surviving are two sons, John F. Siewert II, of Peoria, and Eric A. Siewert of Toulon; granddaughter, Brittney K. Beall (Josh); great-grandson, Baker Beall of Bloomington; and a sister, Marian (Tom) Persich of West Peoria. One son, David J. Siewert preceded him in death on February 9, 2021.
He graduated from Manual High School in 1958. After graduation he worked at Ladish Co. in Cudahy, WI, for two years. He received his Bachelor of Science degree in Mechanical Engineering and a Master Degree in Engineering Administration from Bradley University. He was a Registered Professional Engineer in the State of Illinois and was an engineer at Komatsu in Peoria, earning two US Patents, and retired there after 30 years in 2000.
His main purpose in life was his family and his wife of 65 years.
A Celebration of Life will take place at a later date. Condolences and memories may be shared through Davison-Fulton.com
