I bought a Chevy Cruze 1LT 2014 about a month ago with 66k miles. It's been running great, only thing I had to change was the break booster and master cylinder. I've noticed today that when the car is on and parked there is this steady ticking or clicking sound. It's very faint, not fast but stecy in the sense that is continuous.I has a 1 second interval in between each ticking. I was wondering if this is normal for the car since the engine is already at high mileage. When I had the master cylinder and break booster replace the mechanic said everything else was good, I'm just curious to know what the sound is.