BOLT 7X0391 - Caterpillar

Scheduling a Major Overhaul
The need for a major overhaul is determined by several factors. Some of those factors are the same factors that determine the in-frame overhaul:
An increase of oil consumption
An increase of crankcase blowby
A decrease and variation of cylinder compressionOther factors must also be considered for determining a major overhaul:
Power output
The service hours of the engine
Reduced oil pressure
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 serviced. 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 Caterpillar dealer about scheduling a major overhaul.Note: The generator or 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.Major Overhaul Information
A major overhaul includes all of the work that is done for top end overhauls and in-frame overhauls. Additional parts and labor are required in order to rebuild the engine. In some cases, the engine is relocated for disassembly.For the major overhaul, all of the bearings, seals, gaskets, and components that wear are disassembled. The parts are cleaned. The parts are inspected. If necessary, the parts are replaced. The crankshaft is measured for wear. The crankshaft may require regrinding. Alternatively, the crankshaft may be replaced with a Caterpillar replacement part.Your Caterpillar dealer can provide these services and components. Your Caterpillar dealer can ensure that the components are operating within the appropriate specifications.The following definitions explain the terminology for the services that are performed during an overhaul:Inspect - Inspect the components according to the instructions that are in Caterpillar reusability publications. Refer to Guidelines for Reusable Parts and Salvage Operations, SEBF8029, "Index of Publications on Reusability or Salvage of Used Parts". The guidelines were developed in order to help Caterpillar dealers and customers to avoid unnecessary expenditures. New parts are not required if the existing parts can still be used, reconditioned, or repaired. If the components are not in the reusability guidelines, refer to the Service Manual, "Specifications" module.Rebuild - The component can be reconditioned in order to comply with reusability guidelines.Replace - The service life of the part is exhausted. The part may fail before the next maintenance interval. The part must be replaced with a part that meets functional specifications. The replacement part may be a new part, a CAT remanufactured part, a rebuilt part, or a used part. Some worn components may be exchanged with your Caterpillar dealer. Consult your Caterpillar dealer about repair options for your engine.If you elect to perform an overhaul without the services of a Caterpillar dealer, be aware