TM    5-2815-241-34&P TROUBLESHOOTING  ON  ENGINE  TEST  STAND  –  CONTINUED MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION 21.   MECHANICAL   KNOCKS. Step 1. Step  2. Step  3. Step  4. Step  5. Step  6. Check vibration damper and flywheel for looseness and damage. Tighten  loose  bolts. Replace damaged vibration damper or flywheel. Check push tubes and cam followers for damage. Replace  damaged  push  tubes  (page  2-33)  and  cam  follower (page  2-47). Check for broken piston rings. Replace  broken  piston  rings  (page  2-220). Check for scored pistons and cylinder sleeves. Replace  scored  pistons  (page  2-220)  or  cylinder  sleeves (page  2-140). Check  for  correct  main  and  connecting  rod  bearing  clearance. Replace  bearings  with  proper  size.  Repair  crankshaft  (page  2-214 or 2-220). Check for excessive crankshaft end play. Replace  thrust  bearing  with  oversize,  repair  crankshaft  (page  2-214). 22. OIL  TEMPERATURE  TOO  HIGH. Step 1. Check crankcase oil level. Refill to proper level and drain excess oil. Step  2. Check for high engine temperature or defective thermostat. Replace  defective  thermostat. Step  3. Check  all  hoses,  connections,  and  gaskets  for  leaks,  allowing  air  into  cooling system. Repair or replace leaking hoses, connections, and gaskets. 23.  SLUGGISH  ENGINE  ACCELERATION. Step 1. Check  filter,  gaskets,  connections,  and  suction  lines  for  air  leaks. Replace  defective  filter,  leaking  gaskets,  connections,  and  lines. Step 2. Check all fuel lines for bends, breaks, or damage causing restriction. Repair or replaced restricted fuel lines. Step 3. Check  injector  timing  (page  2-106). Reset  injector  timing. 2-433