I'm also looking for answers to this question - its hard to find good technical/educational content that's not "pop engineering" or just product design.
Embedded.fm has a podcast covering a lot of engineering topics. I haven't listened to All About Circuit's podcast "Moore's Lobby" or The Amp Hour Electronics Podcast, but they are on my to-listen list. The Making Chips podcast covers the manufacturing sector and seems pretty popular. Pumps & Systems magazine also has a good podcast covering fluid pumps, motors & drives, instrumentation & controls, industry news, etc.
I also really liked the book version of "The Perfectionists: How Precision Engineers Created the Modern World," which was entertaining and has an audiobook version.