8M2008293 Mercruiser NUT, (.437-20)

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Note: The procedures have been listed in order of probability. Complete the procedures in order.
Table 1
Troubleshooting Test Steps Values Results
1. Misreading Oil Level
A. Accurately measure the consumption of oil and fuel over a period of 50 engine hours.
Oil level
Result: The oil consumption is less than 0.08% of the fuel consumption.
Oil consumption is within specification. Return the unit to service
Result: The oil consumption is greater than 0.08% of the fuel consumption.
Proceed to Test Step 2.
2. Oil Leaks
A. Check for evidence of oil leaks on the engine.
B. Check for evidence of oil in the coolant.
Oil leaks
Result: An oil leak is identified.
Repair: Rectify the cause of the oil leak.
Result: Oil is present in the coolant.
Repair: Refer to Troubleshooting, "Coolant Contains Oil".
No oil leaks are identified
Proceed to Test Step 3.
3. Engine Crankcase Breather
A. Check the engine crankcase breather for blockage or restrictions.
B. Check for excessive oil from the outlet of the breather.
Breather
Result: The engine crankcase breather is blocked or restricted.
Repair: Clear the blockage or restriction.
Result: Excessive oil is ejected from the outlet of the breather.
Repair: Investigate the cause of the excessive oil content in the breather flow. If the breather filter element is saturated with oil, replace the filter.
Result: No oil is ejected through the breather.
Proceed to Test Step 4.
4. Oil Level
A. Check for a high oil level in the engine.
Oil level
Result: The oil level in the engine is high.
Repair: Make sure that the oil is not contaminated with fuel. Refer to Troubleshooting, "Oil Contains Fuel".
Make sure that the oil is not contaminated with coolant. Refer to Troubleshooting, "Oil Contains Coolant".
Remove the excess oil.
Result: The oil level is OK.
Proceed to Test Step 5.
5. Air Intake and Exhaust System
A. Check the air filter restriction indicator, if equipped.
Check the air intake and the exhaust system for the following defects:
Signs of dirt ingress
Blockages
Restrictions
Damage to the air intake and exhaust lines and hose
Air intake and exhaust system
Result: The air filter restriction indicator has operated or the air filter is blocked.
Repair: Make sure that the air filter is clean and serviceable. If necessary, replace the air filter.
Result: The air intake or the exhaust system is blocked, restricted, or damaged.
Repair: Repair the air intake or the exhaust system, as required.
Result: The air intake or the exhaust system is OK.
Proceed to Test Step 6.
6. Turbochargers
Note: The turbochargers that are installed on this engine are non-serviceable items. If any mechanical fault exists, then the faulty turbocharger must be replaced.
A. Check that the oil drains for the turbochargers are not blocked or restricted.
B. Remove the turbocharger compressor outlet ducts to check for evidence of a turbocharger internal oil leak.
Turbochargers
Result: The oil drain for a turbocharger is blocked or restricted.
Repair: Remove the blockage or restriction. If necessary, replace the oil drain line.
Result: A turbocharger has an internal oil leak.
Repair: Replace the faulty turbocharger. Check the front face of the Diesel Particulate Filter (DPF) for contamination with oil.
If oil is found on the inlet face of the DPF, refer to Troubleshooting, "Exhaust System Contains Oil".
Check that the repairs have eliminated the faults.
Result: The turbochargers are OK.
Proceed to Test Step 7.
7. Low Compression (Cylinder Pressure)
A. Perform a compression test. Refer to Systems Operation, Testing, and Adjusting, "Compression - Test".
Cylinder compression
Result: The results of the compression test are outside the specifications.
Repair: Investigate the cause and rectify any faults.
Note: Possible causes of low compression are shown in the following list:
Loose glow plugs
Worn piston
Worn piston rings
Worn cylinder bores
Worn valves
Faulty cylinder head gasket
Damaged cylinder head
Result: The results of the compression test are OK.
Contact the Dealer Solutions Network (DSN).