I checked that one out, he added diesel idling sound to Submarine waves lap.wav so you hear rumbling when not moving, but he failed to reduce volume in the Vapor Siaj.wav file so it's still "white noise" hissing that overpowers the diesel sound.
Reminder, you are checking the file settings when you first open it, right?
Get in the habit of looking at the original settings and compare them to what this says when you save the file, if they don't match click the configure button and change the settings before clicking OK.