Method for quickly judging low oil pressure of diesel engine

Low oil pressure of the engine, the diesel engine is the use and maintenance of common faults in, when the diesel engine in a hot car idling the engine oil pressure is lower than 0.1Mpa, and high speed is lower than 0.2MPa, generally considered low oil pressure. First introduce the oil pressure is too low, simple diagnosis method.

First, appearance inspection

1, check the quality and quantity of the engine oil

When the engine oil pressure is too low, the engine oil should be checked to meet the requirements. The amount of oil is too small, the fault is obvious, such as the amount of oil in line with the requirements or excessive, should carefully observe whether the diesel oil, water. If the oil is mixed with diesel, the oil becomes diluted and the viscosity drops, resulting in low oil pressure.

2. Observe the oil pressure sensor and the oil pressure gauge

Turn on the power supply (not starting the diesel engine at this time), observe whether the pointer of the oil pressure gauge moves and return exactly to "0"". If the indicator of the oil pressure gauge does not move or can not return to "0", the oil pressure gauge fails or the oil pressure sensor fails or the circuit fault occurs.

Can be connected with a self-made direct pressure oil pressure gauge on the main oil channel (pressure restructuring table 0.1~1.0MPa), start the engine, if the direct pressure low pressure gauge on the diesel engine is sound, can be first on the oil passage of the diesel engine high pressure valve and pressure gauge on the crude oil filter the pressure regulating valve to debug, to observe the effect of debugging.

Two 、 in machine inspection

1. Inspection of oil discharge tank

When the appearance inspection, debugging is invalid, should be put in the net oil, remove the oil pan, and check the oil pan: whether Babbitt alloy cast, especially the massive shedding and other abnormal conditions: filter oil filter is blocked: the oil suction tube and the oil outlet pipe is welded jam, each end is solid and effective: oil pump cover strong sealing effectiveness; gear oil pump shaft and bushing wear is abnormal.

2 pressure and leakage inspection

The above observation, inspection that all meet the requirements, but also failed to find the oil pressure caused by the fault is too low, generally do not rush to disassemble or replace the relevant parts. According to the experience, we can connect the main oil duct with compressed air (a joint which corresponds to the thread size of the main oil path and a high-pressure hose connected with the air source), and the air pressure should be 0.4~0.5MPa. Direct observation or touch the main bearings, connecting rod bearings at the gap, compressed air leaks, and observe the analysis of the following common compressed air leakage anomalies:

(1) in similar bearings, a certain bearing leak of compressed air volume is larger, more urgent, generally this bearing has Babbitt alloy fall off or bearing wear too big situation.

(2) there is obvious air leakage at the oil pump shaft and bushing, it can be judged that the internal wear of the oil pump is too large.

(3) the cylinder body installed on the rotor side filter has obvious migration air leakage, indicating the rotor shaft wear is too large.

(4) there is air leakage on the inside of the cylinder of the oil filter, usually the gasket of the oil filter assembly is damaged or fitted in the middle.

(5) there is obvious air leakage at the timing gear chamber, which should generally be judged as the imbalance between the idle gear and the shaft.

(6) the main oil channel at the inside of the cylinder or other compressed air leaks may determine the casting sand holes or cracks on the oil channel, especially the new cylinder block.

(7) if necessary, can also remove the cylinder cover, leak check valve rocker mechanism, such as leakage uneven, its correlation with too loose (when crank crankshaft).

After checking, you can determine the reasons for low oil pressure, and thus the right remedy, find solutions.