How To Eliminate Low Or High Oil Pressure Of Diesel Generator Set

When we checked the failure of diesel generator set, we found that the oil pressure gauge had no indication or the indication was lower than the specified value: 0.15 MPa~0.4 MPa (1.5~4 kgf/c ㎡) or the oil pressure gauge indicated normal when the machine was just started, then decreased, or even zero. The indication of the diesel generator set oil pressure gauge exceeds the specified value, and the engine power decreases. Next, the editor of Jiangsu Starlight Power will share with you the troubleshooting methods for diesel generator set oil pressure is too low or too high.

1、 The oil pressure is too low.

Cause:

① Insufficient oil.

② The oil viscosity is too small (low grade, high temperature, mixed with fuel or water).

③ The pressure limiting valve is improperly adjusted and the spring becomes soft.

④ The oil pressure gauge and pressure sensing plug fail.

⑤ The oil filter screen and oil pipeline are blocked.

⑥ There is oil leakage in the lubricating oil passage.

⑦ Poor oil pumping capacity of the oil pump: the wear of the driving and driven gears of the oil pump causes excessive clearance between them, or the clearance between the gear and the pump cover is too large.

⑧ The clearance between bearings (bearings at crankshaft, connecting rod and camshaft) is too large.

Troubleshooting:

① Check the quantity and quality of the engine oil: if the engine oil pressure is too low, stop the diesel engine first, wait for 3~5min, and then draw out the oil dipstick to check the quantity and quality of the engine oil.

If the oil quantity is insufficient, add oil with the same brand as the oil in the oil basin. If the viscosity of the oil is low, the oil level rises, and there is a smell of "raw oil", it means that the oil is mixed with fuel. If the oil color is milky white, it means that water has seeped into the oil. Check and eliminate the oil leakage or water leakage, and replace the oil as required.

The oil pressure of the diesel engine will also be reduced if the oil of the corresponding brand is not replaced in time due to seasonal changes, or the added oil brand is inconsistent with the oil brand in the oil basin.

In the process of use, if the diesel engine overheats, it should be considered that the decrease of oil pressure may be caused by the oil thinning due to the high oil temperature. In this case, remove the fault that causes the temperature of the diesel engine to be too high, and then start the generator set after the oil cools down, and the oil pressure will be normal.

② Adjust the pressure limiting valve and check the pressure limiting valve spring: first adjust the pressure limiting valve. If it can be adjusted to the normal pressure, it is improper adjustment of the pressure limiting valve. If the adjustment of the pressure limiting valve is invalid, check whether the spring elasticity of the pressure limiting valve is weakened.

③ Check the oil pressure gauge and pressure sensing plug: check the oil pressure gauge by using the new and old comparison method. Remove the original oil pressure gauge and install a new oil pressure gauge for comparison and judgment.

The method to check the pressure sensing plug is to remove the pressure sensing plug from the cylinder block, block the plug hole with a rag, and briefly start the machine. If the oil is sprayed sufficiently from the oil passage without bubbles, the pressure sensing plug is invalid. If the oil is insufficiently sprayed from the oil passage and bubbles are generated, it indicates that the low oil pressure may be caused by the blocked oil pipeline.

④ Check the oil filter, oil pump and each oil passage: remove the oil filter, turn the crankshaft, and observe the oil outlet passage of the oil pump. If there is little or no oil, it may be that the oil pump does not pump oil or the oil filter is blocked. Check and repair the oil pump or clean the oil filter.

Remove the oil pan and check whether the oil filter is blocked by oil dirt, or whether the oil pump is excessively worn and the pump oil pressure is insufficient. If there are bubbles in the lubricating oil sprayed from the oil passage, it means that the oil pump and the oil inlet connecting pipe joint of the oil pump are broken or the joint is loose.

⑤ Check the bearing clearance: if the bearing clearance at the crankshaft, connecting rod and camshaft is too large, the oil pressure can reach the normal value due to the high viscosity of the oil when starting the machine. However, when the machine heats up, the viscosity of the oil decreases, and the oil is squeezed from both sides of the bearing bush, thus reducing the oil pressure.

2、 The oil pressure is too high.

Fault cause:

① The oil viscosity is too high.

② The pressure limiting valve is improperly adjusted or the spring is too hard.

③ The oil filter is blocked and the bypass valve does not open.

④ The clearance of each bearing is too small.

⑤ The oil pipe behind the oil pressure gauge is blocked.

Troubleshooting:

① Check the viscosity of the engine oil. Take the engine oil scale out of the crankcase, drop a few drops of engine oil on your fingers, and rub your fingers to see if the viscosity of the engine oil is too high. When the viscosity is too high, it may be that the oil grade is incorrect, and the oil of appropriate grade should be replaced.

② Check the pressure limiting valve spring and bypass valve spring to see if they are pressed too tightly, or if the spring is too strong to open, which should be adjusted, cleaned or replaced in time.

③ Check the clearance of each bearing and the oil pipes in the cylinder block. For the newly repaired engine, check whether the bearings are too tight and whether the oil passages to the crankshaft bearings in the cylinder block are blocked. If it is blocked, it is most likely to cause tile burning accident.

The low oil pressure of the diesel generator set will cause great harm to the Yuchai diesel generator set. The light ones will accelerate the wear of the moving parts, and the heavy ones will cause serious accidents such as burning the bearing pads and holding the crankshaft, causing unnecessary losses.

Jiangsu Starlight Electricity Equipments Co.,Ltd. was founded in 1974, as a wholly-owned subsidiary of Jiangsu Starlight Power Group, it is one of the earliest manufacturers of generator sets in China. Starlight Power has 64 sales services, long-term technical advice for users, free debugging, free maintenance, free training services. For more details, please contact us with sales@dieselgeneratortech.com.