STEM 8J4492 - Caterpillar

Severe Operation
Severe 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
InstallationRefer 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 lifeBecause 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 Factors
Extreme Ambient Temperatures
Extended 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".Cleanliness
Unless 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 approvedImproper Maintenance Practices
Extension of maintenance intervals
Not using recommended fuel, lubricants, and antifreeze/coolantOverhaul Information
An overhaul is replacing the major worn components of the engine. An overhaul interval is a maintenance interval that is planned. The engine is rebuilt with certain rebuilt parts or new parts that replace the worn parts.An overhaul also includes the following maintenance:
Inspection of all the parts that are visible during the disassembly
Replacement of the seals and gaskets that are removed
Cleaning of the internal passages of the engine and the engine blockMost owners will save money by overhauling the engine at the intervals that are recommended in this Operation and Maintenance Manual. Consider the graph in Illustration 1.
Illustration 1 g00745964
(Y) Cost
(X) Time
(1) Cost of maintenance and repair that is planned
(2) Cost of maintenance and repair that is not planned In Illustration 1, line (1) represents the maintenance and repair costs for an owner that followed the recommendations for inspection, maintenance, and repair. The peaks represent overhauls.Line (2) represents the maintenance and repair costs for an owner that chose to operate beyond the recommended intervals. The initial cost of the “repair-after-failure” philosophy is lower. Also, the first overhaul was delayed. However, the peaks are significantly higher than the