Engine Instrument Systems Which of the following instrument discrepancies require replacement of the instrument? 1. Red line missing from glass. 2. Glass cracked. 3. Case paint chipped. 4. Will not zero out. 5. Pointer loose on shaft. 6. Mounting screw loose. 7. Leaking at line B nut. 8. Fogged. a. 2, 3, 7, 8. b. 2, 4, 5, 8. c. 1, 2, 4, 7.