Some factors that are important for determining the overhaul intervals include the following considerations:
- Performance of preventive maintenance
- Use of recommended lubricants
- Use of recommended coolants
- Use of recommended fuels
- Proper installation
- Operating conditions
- Operation within acceptable limits
- Engine load
- Engine speed
Generally, engines that are operated at a reduced load and/or speed achieve more service life before an overhaul. However, this is for engines that are properly operated and maintained.
Other factors must also be considered for determining a major overhaul:
- The total amount of fuel consumption
- The service hours of the engine
- An increase of oil consumption
- An increase of crankcase blowby
- The wear metal analysis of the lube oil
- An increase in the levels of noise and vibration
-An increase of wear metals in the lube oil indicates that the bearings and the surfaces that wear may need to be serviced.
-An increase in the levels of noise and vibration indicates that rotating parts require service.
Note: It is possible for oil analysis to indicate a decrease of wear metals in the lube oil.
The cylinder liners may be worn so that polishing of the bore occurs. Also, the increased use of lube oil will dilute the wear metals. Monitor the engine as the engine accumulates service hours. Consult your Caterpillar dealer about scheduling a major overhaul.
Note: The driven equipment may also require service when the engine is overhauled. Refer to the literature that is provided by the OEM of the driven equipment. Using Fuel Consumption For Calculating the Overhaul IntervalsExperience has shown that maintenance intervals are most accurately based on fuel consumption. Fuel consumption corresponds more accurately to the engine load.
Tables 1, 2, and 3 list average ranges of fuel consumption and service hours for a load factor of approximately 60 percent. Use the range of fuel consumption only as a guideline.
Table 1
Maintenance Interval Schedule Service Hours and Fuel Consumption for 3508B and 3508 Engines with the EUI System (1) Interval Rated Up To 1300 RPM Rated 1301 To 1600 RPM Rated 1601 To 1800 RPM 250 Service Hours 22700 L (6000 US gal) 27700 L (7200 US gal) 32000 L (8500 US gal) 500 Service Hours 45400 L (12000 US gal) 54400 L (14400 US gal) 64000 L (17000 US gal) 1000 Service Hours 89000 L (23500 US gal) 109000 L (28800 US gal) 128000 L (34000 US gal) 2000 Service Hours 178000 L (47000 US gal) 218000 L (57600 US gal) 257000 L (68000 US gal) 3000 Service Hours 267500 L (70500 US gal) 327500 L (84000 US gal) 386500 L (102000 US gal) 6000 Service Hours 535000 L (141000 US gal) 654000 L (173000 US gal) 774000 L (204000 US gal) Top End Overhaul 11000 Service Hours 9000 Service Hours 7500 Service Hours 1000000 L (264000 US gal) Second Top End Overhaul 22000 Service Hours 18000 Service Hours 15000 Service Hours 2000000 L (528000 US gal) Major Overhaul 33000 Service Hours 27000 Service Hours 22500 Service Hours 3000000 L (792000 US gal) ( 1 ) Fuel consumption is based on a load factor of approximately 60 percent.
Table 2
Maintenance Interval Schedule Service Hours and Fuel Consumption for 3512B and 3512 Engines with the EUI System (1) Interval Rated Up To 1300 RPM Rated 1301 To 1600 RPM Rated 1601 To 1800 RPM 250 Service Hours 33400 L (8800 US gal) 41000 L (10800 US gal) 48500 L (12800 US gal) 500 Service Hours 66800 L (17600 US gal) 82000 L (21600 US gal) 97000 L (25600 US gal) 1000 Service Hours 133500 L (35000 US gal) 164000 L (43200 US gal) 194000 L (51200 US gal) 2000 Service Hours 267000 L (70000 US gal) 328000 L (86400 US gal) 388000 L (102400 US gal) 3000 Service Hours 398000 L (105000 US gal) 491000 L (129600 US gal) 582000 L (153600 US gal) 6000 Service Hours 796000 L (210000 US gal) 982000 L (259200 US gal) 1164000 L (307200 US gal) Top End Overhaul 11000 Service Hours 9000 Service Hours 7500 Service Hours 1500000 L (395000 US gal) Second Top End Overhaul 22000 Service Hours 18000 Service Hours 15000 Service Hours 3000000 L (790000 US gal) Major Overhaul 33000 Service Hours 27000 Service Hours 22500 Service Hours 4500000 L (1185000 US gal) ( 1 ) Fuel consumption is based on a load factor of approximately 60 percent.
Table 3
Maintenance Interval Schedule Service Hours and Fuel Consumption for 3516B and 3516 Engines with the EUI System (1) Interval Rated Up To 1300 RPM Rated 1301 To 1600 RPM Rated 1601 To 1800 RPM 250 Service Hours 44000 L (11600 US gal) 53000 L (14000 US gal) 64500 L (17000 US gal) 500 Service Hours 88000 L (23200 US gal) 106000 L (28000 US gal) 129000 L (34000 US gal) 1000 Service Hours 176000 L (46500 US gal) 212000 L (56000 US gal) 258000 L (68000 US gal) 2000 Service Hours 352000 L (93000 US gal) 424000 L (112000 US gal) 516000 L (136000 US gal) 3000 Service Hours 528700 L (139500 US gal) 636700 L (168100 US gal) 773000 L (204000 US gal) 6000 Service Hours 1056000 L (279000 US gal) 1272000 L (336000 US gal) 1548000 L (408000 US gal) Top End Overhaul 11000 Service Hours 9000 Service Hours 7500 Service Hours 2000000 L (528000 US gal) Second Top End Overhaul 22000 Service Hours 18000 Service Hours 15000 Service Hours 4000000 L (1056000 US gal) Major Overhaul 33000 Service Hours 27000 Service Hours 22500 Service Hours 6000000 L (1584000 US gal) ( 1 ) Fuel consumption is based on a load factor of approximately 60 percent.
Use the actual records of fuel consumption, when possible. If the actual records are not available, use the following procedure in order to estimate the fuel consumption.
1. Estimate the average percent of the load for the operation of the engine.
2. Refer to the fuel consumption data in the Technical Marketing Information (TMI) for your engine. This will determine the fuel consumption for the percent of the load that was estimated in Step 1. Use this figure as variable "F" for the equation in Table 4. For more information about the Technical Marketing Information (TMI) for your engine, consult your Caterpillar dealer.
Table 4
Equation For Calculating Overhaul Intervals F/R = H "F" is the estimated total amount of fuel consumption of the engine. "R" is the rate of fuel consumption in liters per hour or gallons per hour. "H" is the number of estimated hours until the overhaul interval. Oil Consumption as an Overhaul IndicatorOil 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. Severe OperationSevere operation is the use of an engine that exceeds current published standards for that engine.
Caterpillar maintains standards for the following engine parameters:
- Horsepower
- Range of rpm
- Fuel consumption
- Fuel quality
- Altitude
- Maintenance intervals
- Selection of oil
- Selection of coolant
- Environmental qualities
- Installation
Refer to the standards for your engine or consult your Caterpillar dealer in order to determine if your engine is operating within the defined parameters. Severe operation can accelerate component wear.
Engines that are operating under severe conditions may need more frequent maintenance intervals for the following reasons:
- Maximum reliability
- Retention of full service life
Because of individual applications, it is not possible to identify all of the factors which can contribute to severe operation. Consult your Caterpillar dealer about the maintenance that is needed for your specific engine.
The following factors can contribute to severe operation: environment, improper operating procedures and improper maintenance practices. Environmental FactorsExtreme Ambient TemperaturesExtended operation in environments that are extremely cold or hot can damage components. Valve components can be damaged by carbon buildup if the engine is frequently started and stopped in very cold temperatures. Extremely hot inlet air reduces the performance capabilities of the engine. Note: See this Operation and Maintenance Manual, "Cold Weather Operation" topic (Operation Section), or see Supplement, SEBU5898, "Cold Weather Recommendations". CleanlinessUnless the equipment is cleaned regularly, extended operation in a dirty environment and in a dusty environment can damage components. Built up mud, dirt, and dust can encase components. This can make maintenance difficult. The buildup can contain corrosive chemicals. Corrosive chemicals and salt can damage some components.
Improper Operating Procedures
- Extended operation at low idle
- Minimum cool down periods after high load factor operation
- Operating the engine beyond the guidelines for the engine rating
- Operating the engine at loads that are greater than the rated load
- Operating the engine at speeds that are greater than the rated speed
- Use of the engine for an application that is not approved Improper Maintenance Practices
- Extension of maintenance intervals
- Not using recommended fuel, lubricants, and coolant/antifreeze