I was watching "Roadkill" the other day. On the show a couple of mechanics try to pass themselves off as bumpkin mechanics muddling through fixing cars. But every once in a while they'll slip up. For example, one of them said the engine was behaving in an adiabatic way. This is a term one only learns taking a college level thermodynamics course.

It's hard to fake having an engineering education, and if you have one it should show in an interview whether or not you have the degree.