Now that's an interesting comment, because I believe in "The Great Escape" there's a scene where he's pretending to be deaf, and a Nazi fires a pistol unexpectedly behind his head to test him, and he doesn't flinch (this could be a completely different movie and actor - Stalag 17? - but I think this is right). Anyway, if so, McQueen would have been using his lack of body movement to indicate his deafness, maybe as an inside joke.
Probably a fun thing to do for the crew too which had to work around his handicap. He could hear but his loss was profound. Very tiring to be in a social situation with such a problem. Explains why he (and others) hang back a little and look around a lot.
He wasn’t that deaf — I spoke to him on the phone as well as in person — but he did look at the face of whomever he was speaking to with a fiery intensity.