921803-0410 Tohatsu SCREW

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's 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, Caterpillar Inc. recommends a scheduled engine overhaul by your Caterpillar dealer before the engine fails. 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.Rebuild or Exchange
Cylinder Head Assembly, 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
ReplacingUsing out-of-spec parts 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
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 bearingsInspect 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
During an overhaul, Caterpillar Inc. recommends the removal of the oil cooler core. Clean the oil cooler core. Then, pressure test the oil cooler core.
Do not use caustic cleaners to clean the core.Caustic cleaners can attack the internal metals of the core and cause leakage.
Note: Use this cleaning procedure to clean the oil cooler core.
Remove the oil cooler core.
Remove any debris from the oil cooler core. To remove debris from the oil cooler core, turn the oil cooler core onto one end.
Flush the oil cooler core internally with cleaner in order to loosen foreign substances. This will also help to remove oil from the oil cooler core.Note: Caterpillar Inc. recommends the use of Hydrosolv Liquid Cleaners. Table 1 lists the Hydrosolv Liquid Cleaners that are available from your Caterpillar dealer.
Table 1
HydrosolvLiquid Cleaners    
Part Number     Description     Size    
1U-8812     Hydrosolv4165    
4 L (1 US gallon)    
1U-5490    
19 L (5 US gallon)
8T-7570    
208 L (55 US gallon)
1U-8804     Hydrosolv100    
4 L (1 US gallon)    
1U-5492    
19 L (5 US gallon)
8T-5571    
208 L (55 US gallon)
Use steam to clean the oil cooler core. This removes any remaining residue from the cleaner. Flush the fins of the oil cooler core. Remove any other trapped debris.
Wash the oil cooler core with hot, soapy water. Rinse the oil cooler core thoroughly with clean water.