TM    10-3930-638-24&P 2-9.  ENGINE  TROUBLESHOOTING  (cont) MALFUNCTION TEST OR lNSPECTION CORRECTIVE ACTION 2. EXCESSIVE FUEL USAGE Step 1. Check fuel lines for leakage or damage. a. If fuel lines are leaking or damaged, repair or replace (para 2-15d(2)). b. If fuel lines are okay, proceed to step 2 below. Step 2. Check fuel tank for leakage or damage. a. If fuel tank leaks or is damaged, notify direct support maintenance. b. If fuel tank is okay, proceed to step 3 below. WARNING If NBC exposure is suspected, all air filter media should be handled by per- sonnel wearing protective equipment. Consult your unit NBC officer or NBC  NCO  for  appropriate  handling  or  disposal  procedures. Step 3. Check if air cleaner indicator red flag is in view. a. If in view, depress reset button on top of indicator and check that red flag disappears from view. (If red flag does not disappear from view, replace air cleaner indicator as described in para 2-15c.) Crank engine and check if red flag is in view; if@ flag is in view, service air cleaner (para 2-15c). b. If red flag is not in view, notify direct support maintenance. 2-11.  EXHAUST  SYSTEM  TROUBLESHOOTING MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION 1. EXCESSIVE  EXHAUST  NOISE Step 1.    Check muffler and exhaust pipe for cracks and holes. a. If muffler or exhaust pipe are cracked or holes are observed, replace (para 2-16). b. If muffler and exhaust pipe check okay, proceed to step 2 below. Step 2. Squirt small amount of oil on muffler gasket area where muffler connects to exhaust manifold. With engine idling, check if air bubbles can be seen, indicating damaged gasket. a. If air bubbles are seen, replace gasket (para 2-16). b. If air bubbles are not seen, proceed to step 3 below. Step 3. Squirt small amount of oil on exhaust manifold in gasket area where exhaust manifold is mounted to cylinder  head. With engine idling, check if air bubbles can be seen, indicating damaged gasket. a. If air bubbles are seen, replace gasket (para 2-14e). b. If muffler and exhaust pipe check okay, proceed to step 4 below. Step 4. Check exhaust manifold for cracks or holes. Replace exhaust manifold (Para 2-14e). 2-24 Change   5