TM10-3930-660-20 Table 2-3. Mechanical Troubleshooting (Cont’d) MALFUNCTION TEST  OR  INSPECTION CORRECTIVE  ACTION Step 2.  Check for engine running too cold. Refer to Coolant Temperature Below Normal section, Step 22 of Cooling System Troubleshooting. Step 3. Check engine oil for viscosity too thick. a. Check that the correct engine oil is being used, see LO 10-3930-660-12. b. Replace engine oil if necessary, para. 4-3. 13. ENGINE LUBRICATING  OIL  LOSS Step 1. Check for external leaks. Inspect engine for external oil leaks. Step 2. Check crankcase for oil overfill. Verify that the crankcase is not overfilled. Drain oil to correct level, if necessary, para. 4-3. Verify that the oil is at correct mark on  dipstick. Step 3. Check for turbocharger oil leaking to the air intake. Replace oil and lines or gaskets as necessary, para. 5-7 thru 5-9. 14. CONTAMINATED ENGINE LUBE OIL Step 1. Check for coolant in the engine oil, internal engine component leaks. Refer to Test 23, Coolant Loss in this table (Table 2-3). Step 2. Check for excessive engine oil sludge. a. Replace engine oil and filter, para. 4-3. b. Check that the correct engine oil is being used; see LO10-3930-660-12. Step 3. Check for fuel in the engine oil, engine operating too cold. If either condition is found, review vehicle operation for excessive idling resulting in the engine running below normal temperature. 2-34