Lubrication System Servicing and Troubles

The useful service life of the engine largely depends on the purity of the oil the engine is lubricated with. Contaminated oil makes the rubbing surfaces of the engine working parts wear rapidly. The crankcase oil can be most simply checked for quality (purity) by the following method. Apply a few drops of the oil onto a sheet of white, preferably filter paper. If the oil is contaminated, it will leave, while spreading over the paper, a dark spot in the center of the sheet, which indicates that the active oil additives separate from the oil. In clean oil, the additives are held in fine suspension and will form a ring on the filter paper.

The servicing of the engine lubrication system involves the following procedures: checking the oil level in the engine crankcase, checking all the connections of the system for leaks, monitoring the oil temperature and pressure while warming the engine up and while running it under load, flushing the system, and changing the crankcase oil.

As a matter of routine maintenance of the lubrication system of the tractor or automobile engine, the driver must check the crankcase oil level every shift, but not earlier than 10 min after the engine has been stopped, and top up the system should the oil level prove to be below the upper marking on the dipstick; check the system for oil leaks and eliminate any leaks revealed; watch the readings of the oil pressure gauge during engine operation; check the operation of the centrifugal oil filter by listening to its rotor after the engine has been stopped. If the noise produced by the filter rotor revolving by inertia lasts for less than 30 s (this indicating that the rotor is excessively contaminated), the filter must be disassembled and the jet nozzles of its rotor cleaned.

EVERY 120 HOURS OF OPERATION the rotor of the centrifugal oil filter must be cleaned. To do this, remove the filter hood and rotor from the spindle, disassemble the rotor, remove deposits from the rotor walls and wash all the component parts of the rotor with diesel fuel; use a length of copper wire 1.5 mm in diameter to clean the jet nozzles of the rotor. Then reassemble the rotor, making sure that the sealing ring of the rotor bowl is placed correctly in its groove in the rotor body, and install the rotor and filter hood in place.

EVERY 240 HOURS OF OPERATION the oil in the engine lubrication system must be changed. Before filling it with fresh oil, the system must be flushed with a mixture of 80% diesel fuel and 20% engine oil. This is done with the aid of a special plant when the engine is stopped.

EVERY 960 HOURS OF OPERATION the oil pan and the oil pick-up of the oil pump must be removed from the engine and washed clean with diesel fuel.

THE MOST COMMON LUBRICATION SYSTEM troubles are as follows: no oil pressure, too low or too high oil pressure, oil contamination with coolant, and oil leaks.

The absence of oil pressure in the system may be caused by low oil level in the oil pan, stuck pressure relief valve of the oil pump, or faulty oil pump drive. These troubles can be removed by adding oil to the oil pan, washing the pressure relief valve, or repairing the oil pump drive, respectively.

Low oil pressure in the system may be caused by lack of oil in the oil pan, enabling air to enter the oil pump, low viscosity of the oil as a result of its overheating, dilution with fuel, or incompatibility with the engine requirements, clogged oil pick-up screen, weak or broken pressure relief valve spring of the oil pump or oil filter, worn oil pump components, or large crankshaft bearing clearances.

To remove the trouble, it is necessary to eliminate successively its causes: add oil to the oil pan, eliminate the causes of oil overheating or change the oil in accordance with the engine manufacturer's recommendations, remove the oil pan and wash clean the oil pick-up screen, wash clean and adjust the pressure relief valve of the oil pump or oil filter, and, if necessary, replace the crankshaft bearing inserts.

High oil pressure in the lubrication system may be caused by high viscosity of the oil or stuck pressure relief valve of the oil filter. To remove the trouble, it is necessary to disconnect the oil cooler from the system, check the oil viscosity and change the oil, if need be, and check the relief valve of the filter and eliminate the causes of its sticking, if any.

If the engine coolant gets into the crankcase oil, one should first of all tighten up the cylinder head nuts and, if necessary, replace the sealing gaskets between the cylinder liners and the cylinder block.

Oil leaks are eliminated by tightening up the respective fasteners and, if necessary, replacing damaged sealing gaskets or leaky components.