Diesel coarse filters equipped with oil-water separation function are all equipped with a water level sensing alarm system. When the water level in the collection cup exceeds the standard, the vehicle dashboard will automatically light up the water level alarm light, which is the most common routine fault reminder for diesel equipment. Many users have insufficient awareness of this fault, either blindly replacing the filter element or ignoring the alarm and continuing to drive, which can easily cause moisture to enter the precision oil circuit and damage engine components. Accurately distinguishing between normal alarms and fault alarms, mastering standardized water discharge processes and troubleshooting techniques, can quickly solve problems and avoid equipment damage.

The water accumulation alarm is a reminder of the normal operation of the filter, not a damage to the filter element. During the entire process of production, transportation, refueling, and storage of diesel, free water will be mixed in. At the same time, the air introduced by the fuel tank vent valve will produce a large amount of water vapor through temperature difference condensation, which will continue to mix into diesel. The core function of a coarse filter is to separate and store this moisture. When the accumulated moisture reaches the sensor warning threshold, the alarm light automatically lights up to remind the user to drain the water in a timely manner and prevent moisture from entering the engine. In humid and rainy areas, open-air oil storage, and poor quality oil conditions, the rate of water accumulation is faster, and the frequency of alarms will significantly increase, which is a normal phenomenon.

Standardized water discharge operation is simple and standardized, and is an essential process for daily basic maintenance. Firstly, park the vehicle and equipment on a flat surface, turn off the engine and let it stand for 5-10 minutes to allow the oil and water in the filter to fully separate and settle to the bottom of the water collection cup, avoiding mixed discharge of oil and water; Next, prepare a dedicated oil receiving container and align it with the drain valve at the bottom of the coarse filter; Slowly open the water valve, drain the accumulated water and turbid oil and water until clear and impurity free pure diesel oil flows out. Immediately tighten the drain valve to prevent oil leakage and intake. It is recommended to drain water once every 7-10 days for regular dry conditions, and once every 3-5 days for wet, rainy, and outdoor work conditions to control the moisture content of the oil circuit from the source.

If the alarm light still stays on after the standard water discharge, it is an equipment failure state, and the five major causes need to be investigated item by item. Firstly, if the sealing of the drain valve is not tight, not tightened, or the sealing gasket is aged or damaged, resulting in abnormal intake and water accumulation in the oil circuit, the valve needs to be tightened and the sealing gasket needs to be replaced; Secondly, the water level sensor probe is attached with oil sludge impurities, causing sensing failure and requiring disassembly to clean the probe stains; Thirdly, if the sensor circuit is loose, damaged, or has poor contact, it is necessary to check the circuit joints and repair the circuit faults; Fourthly, if the water collection cup cracks or the buckle is loose, it cannot store water properly and needs to be replaced with a new water collection cup assembly; Fifth, the filter element has aged and failed, the oil-water separation ability has decreased, and the water cannot settle normally. It is necessary to replace the filter element with a brand new one.

Long term neglect of water accumulation alarms and failure to drain water in a timely manner can lead to serious engine failures. After water enters the high-pressure oil circuit, it will corrode the oil pump plunger and injection needle valve, causing rusting, jamming, and poor atomization of components; Insufficient combustion of fuel containing water can lead to idle shaking, decreased power, white exhaust, and a significant increase in carbon deposits; In severe cases, water accumulation and freezing can block the oil circuit, freeze and crack the components, causing the equipment to stall and fail to start halfway. Adhering to regular and standardized water discharge and timely troubleshooting is a low-cost and high-efficiency maintenance method for protecting diesel engines.