F1669 Mercruiser NUT, (#6-32)

Oil Consumption as an Overhaul Indicator
Oil consumption, fuel consumption, and maintenance information can be used to estimate the total operating cost for your Caterpillar engine. Oil consumption can also be used to estimate the required capacity of a makeup oil tank that is suitable for the maintenance intervals.Oil consumption is in proportion to the percentage of the rated engine load. As the percentage of the engine load is increased, the amount of oil that is consumed per hour also increases.The oil consumption rate (brake specific oil consumption) is measured in grams per kW/h (lb per bhp). The brake specific oil consumption (BSOC) depends on the engine load. Consult your Caterpillar dealer for assistance in determining the typical oil consumption rate for your engine.When an engine's oil consumption has risen to three times the original oil consumption rate due to normal wear, an engine overhaul should be scheduled. There may be a corresponding increase in blowby and a slight increase in fuel consumption.Overhaul Options
Before Failure Overhaul
A planned overhaul before failure may be the best value for the following reasons:
Costly unplanned downtime can be avoided.
Many original parts can be reused according to the standards for reusable parts.
The engine service life can be extended without the risk of a major catastrophe due to engine failure.
The best cost/value relationship per hour of extended life can be attained.After Failure Overhaul
If a major engine failure occurs and the engine must be removed, many options are available. An overhaul should be performed if the engine block or the crankshaft needs to be repaired.If the engine block is repairable and/or the crankshaft is repairable, the overhaul cost should be between 40 percent and 50 percent of the cost of a new engine with a similar exchange core.This lower cost can be attributed to three aspects:
Specially designed Caterpillar engine features
Caterpillar dealer exchange components
Caterpillar Inc. remanufactured exchange componentsOverhaul Recommendation
To minimize downtime, a scheduled engine overhaul by your Caterpillar dealer is recommended. This will provide you with the best cost/value relationship.Note: Overhaul programs vary according to the engine application and according to the dealer that performs the overhaul. Consult your Caterpillar dealer for specific information about the available overhaul programs and about overhaul services for extending the engine life.If an overhaul is performed without overhaul service from your Caterpillar dealer, be aware of the following maintenance recommendations.Unit Fuel Injector
Clean the fuel injector body and replace the O-rings. Replace the O-rings and the gasket on the injector sleeve. Clean the area around the injector seating in the injector sleeve. Refer to the Service Manual for the complete procedure, or consult with your Caterpillar dealer for assistance.Rebuild or Exchange
Cylinder Head Assembly, Connecting Rods, Pistons, Cylinder Liners, Turbocharger, Cylinder Packs, Oil Pump, and Fuel Transfer Pump
These components should be inspected according to the instructions that are found in various Caterpillar reusability publications. The Special Publication, SEBF8029 lists the reusability publications that are needed for inspecting the engine parts.If the parts comply with the established inspection specifications that are expressed in the reusable parts guideline, the parts should be reused.Parts that are not within the established inspection specifications should be dealt with in one of the following manners:
Salvaging
Repairing
ReplacingParts that do not comply with the established inspection specifications can result in the following problems:
Unscheduled downtime
Costly repairs
Damage to other engine parts
Reduced engine efficiency
Increased fuel consumptionReduced engine efficiency and increased fuel consumption translates into higher operating costs. Therefore, Caterpillar Inc. recommends repairing out-of-spec parts or replacing out-of-spec parts.Inspection and/or Replacement
Piston Rings, Crankshaft Bearings, Valve Rotators, and Crankshaft Seals
The following components may not last until the second overhaul.
Thrust bearings
Main bearings
Rod bearings
Valve rotators
Crankshaft sealsCaterpillar Inc. recommends the installation of new parts at each overhaul period.Inspect these parts while the engine is disassembled for an overhaul.Inspect the crankshaft for any of the following conditions:
Deflection
Damage to the journals
Bearing material that has seized to the journalsCheck the journal taper and the profile of the crankshaft journals. Check these components by interpreting the wear patterns on the following components:
Rod bearing
Main bearingsNote: If the crankshaft is removed for any reason, use the magnetic particle inspection process to check for cracks in the crankshaft.Inspect the camshaft for damage to the journals and to the lobes.Note: If the camshaft is removed for any reason, use the magnetic particle inspection process to check for cracks in the camshaft.Inspect the following components for signs of wear or for signs of scuffing:
Camshaft bearings
Camshaft followersCaterpillar Inc. recommends replacing the crankshaft vibration damper.Oil Cooler Core and Aftercooler Core
During an overhaul, the removal of the oil cooler core and the aftercooler core is recommended. The oil cooler core and the aftercooler core should be cleaned and pressure tested.
Do not use caustic cleaners to clean the core.Caustic cleaners can attack the internal metals of the core and cause leakage.
Obtain Coolant Analysis
The concentration of supplemental coolant additive (SCA) should be checked regularly with test kits or with S O S Coolant Analysis (Level 1). Further coolant analysis is recommended when the engine is overhauled.A coolant analysis can be conducted in order to verify the condition of the water that is being used in the cooling system. A full water analysis can be obtained by consulting your local water utility company or an agricultural agent. Private laboratories are also available for water analysis.Caterpillar Inc. recommends an S O S Coolant Analysis (Level 2).S O S Coolant Analysis (Level 2)
An S O S Coolant Analysis (Level 2) is a comprehensive coolant analysis which completely analyzes the coolant and the effects on the cooling system. An S O S Coolant Analysis (Level 2) provides the following information:
Complete S O S Coolant Analysis (Level 2)
Visual inspection of properties
Identification of metal corrosion
Identification of contaminants
Identification of built up impurities (corrosion and scale)S O S Coolant Analysis (Level 2) provides a report of the results of both the analysis and the maintenance recommendations.For more information about coolant analysis, consult your Caterpillar dealer.