TM 10-3930-641-34-1
ENGINE TROUBLESHOOTING (CONT)
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
10. LOUD CLICKING NOISE FROM VALVE COMPARTMENT
Step 1. Check for damaged springs or locks on valves.
Replace springs or locks as needed. (See page 3-255.)
Step 2. Check lubrication in valve compartment.
Look for a strong flow of oil at high rpm and a small flow of oil at low rpm. If there is little or
no oil flow from all passages, repair engine oil pump. If there is little or no oil flow from one
passage, but a sufficient flow from other passages, then the passage is clogged. Clean the passage.
Step 3. Check for too much valve clearance. (See page 3-268.)
Adjust valve clearance. (See page 3-268.)
Step 4. Check for damaged valve bridge.
a. Replace bridge and adjust. (See page 3-255.)
b. Readjust valve clearance. (See page 3-268.)
Step 5. Inspect for bent push rods.
Replace push rods. (See page 3-264.)
Step 6. Remove and inspect camshaft.
Replace if damaged. (See pages 3-273, 3-283.)
Step 7. Inspect valve lifters.
Repair/replace. (See page 3-264.)
Inspect camshaft lobes for damage from lifters. (See page 3-283.)
Replace camshaft if lobes are damaged. (See page 3-273.)
11. LOUD MECHANICAL NOISE IN ENGINE
Step 1. Inspect timing gears for damage.
Replace if necessary. (See page 3-291.)
Step 2. Inspect camshaft for damage.
Replace if necessary see pages 3-273, 3-283.)
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