SUPPORT ASSEM. 7S7625 - 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 condition 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 require servicing. An increase in the levels of noise and vibration indicates that rotating parts require service.Note: Oil analysis can 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 Cat 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. Refer to table 1.
Table 1
Service Hours and Fuel Consumption for the 3512C Engine
Interval Fuel Consumption(1) Fuel Consumption(2)
250 Service Hours 32980 L (8712 US gal) 41534 L (10972 US gal)
500 Service Hours 65960 L (17425 US gal) 83067 L (21944 US gal)
1000 Service Hours 131921 L (34850 US gal) 166138 L (43889 US gal)
2000 Service Hours 263842 L (69700 US gal) 332275 L (87778 US gal)
3000 Service Hours 395765 L (104550 US gal) 498414 L (131667 US gal)
6000 Service Hours 791526 L (209099 US gal) 996824 L (263333 US gal)
Top End Overhaul 1187291 L (313649 US gal) 1495238 L (395000 US gal)
9000 Service Hours
Second Top End Overhaul 2374581 L (627298 US gal) 2990475 L (790000 US gal)
18000 Service Hours
Major Overhaul 34000 Service Hours 27000 Service Hours
4485713 L (1185000 US gal)
(1) Based on 39 percent load factor.
(2) Based on 51 percent load factor.Oil Consumption as an Overhaul Indicator
Oil consumption, fuel consumption, and maintenance information can be used to estimate the total operating cost for your Cat 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