ELBOW-AIR TRANSFER 7C0386 - Caterpillar

Overhaul Intervals
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 speedGenerally, 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 vibrationAn 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 Intervals
Experience has shown that maintenance intervals are most accurately based on fuel consumption. Fuel consumption corresponds more accurately to the engine load. Table 1 lists average ranges of fuel consumption and service hours for 3512Bengines. These tables are based on a load factor of approximately 60 percent.
Table 1
Service Hours and Fuel Consumption for 3512B Engines (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) of fuel    
48500 L (12800 US gal) of fuel    
500 Service Hours    
66800 L (17600 US gal)    
82000 L (21600 US gal) of fuel    
97000 L (25600 US gal) of fuel    
1000 Service Hours    
133500 L (35000 US gal)    
164000 L (43200 US gal) of fuel    
194000 L (51200 US gal) of fuel    
2000 Service Hours    
267000 L (70000 US gal)    
328000 L (86400 US gal) of fuel    
388000 L (102400 US gal) of fuel    
3000 Service Hours    
398000 L (105000 US gal)    
491000 L (129600 US gal) of fuel    
582000 L (153600 US gal) of fuel    
6000 Service Hours    
796000 L (210000 US gal)    
982000 L (259200 US gal) of fuel    
1164000 L (307200 US gal) of fuel    
Top End Overhaul     11000 Service Hours     9000 Service Hours     7500 Service Hours    
1500000 L (395000 US gal) of fuel
Second Top End Overhaul     22000 Service