This script will make cars either have a check engine sound or a squeaking belt noise when their health drops below 700, based on how they're classified as in vehicles.ide.

Poor family cars will have the squeaking serpentine belt sound while rich family cars will have the check engine sound. Alternatively, you can have all cars to have these effects.
There's also an INI file to configure the volume.

Update adds aircraft engine warning for a few planes and helicopters.