3512C HD Locomotive Engine 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 speed

Generally, engines that are operated at a reduced load and/or speed achieve more service life before an overhaul. However, this service life 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 serviced. An increase in the levels of noise and vibration indicates that rotating parts require service.

Note: Oil analysis may 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. Table 1 list average ranges of fuel consumption and service hours for a load factor of approximately 40 percent. Table 2 list average ranges of fuel consumption and service hours for a load factor of approximately 25 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 data 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 3. For more information about the Technical Marketing Information (TMI) for your engine, consult your Cat dealer.

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 bhp). The brake-specific oil consumption (BSOC) depends on the engine load. Consult your Cat dealer for assistance in determining the typical oil consumption rate for your engine.

When engine 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.