Oil lubrication is very important for the engine. If the lubrication system fails, but not timely maintenance, will cause serious damage to the engine. Jetta car installed the oil sound and light alarm system, when the lubrication system is abnormal, the instrument panel on the oil alarm light will light up, such as the speed of more than 2000r / min, the alarm buzzer will ring to remind the driver to pay attention to The The car is running, such as the discovery of oil alarm light, should immediately stop, do not continue to drive down, because the oil lubrication is bad and make the engine damage is a few minutes of effort. After the flame is turned off, the oil level can be pulled out of the oil level check the oil level should be between the highest and lowest scale, such as oil level below the lower limit, should add oil, and then check the alarm light is bright. If the oil alarm light is still lit, you need to check the professional Jetta repair station repair.
    After entering the repair station, the usual inspection method is to first check the oil pressure, remove the cylinder head behind the oil pressure switch, install the oil pressure gauge VAGl527, start the engine, check the oil pressure, idle at least O.36bar, hot car So that the oil temperature increased by 80 ℃, the engine speed stable at 2000r / min, when the oil pressure of at least 2.0bar. If the oil pressure is normal, the oil warning light is still bright, the cause of the failure is generally in the electrical part of the line, then the pressure switch, the relevant line and alarm control unit to check, the specific method is as follows:
    1. Open the ignition switch, but do not start the engine, the oil warning light should be bright, if not bright, can be pulled out of low-voltage switch plug, such as light, then the low-voltage switch is damaged,
    2. Start the engine, idle operation, the oil alarm light should be extinguished, if the light is always bright, unplug the low-voltage switch plug light off, then the low-voltage switch is damaged, should be replaced, such as unplugging low-voltage switch plug end of the lamp, the line exists Short circuit fault
    3. The engine speed is stable at 2000r / min, if the alarm light when there is a beep, you can unplug the high-voltage switch plug (located in the machine seat marked 1.8bar, white), its ground, such as alarm light off, alarm sound Disappear, indicating that the high-voltage switch is damaged, should be replaced, such as unplugging the plug is still alarm, then the high-voltage switch to the instrument line on the road fault;
    4. If the high voltage switch, low voltage switch and the relevant lines are normal, it may be oil alarm control unit failure, can be replaced in the instrument panel on the oil alarm control unit.
    If you check the oil pressure is not normal, and the oil alarm light, you can remove the low pressure switch in the oil pressure gauge, and installed in the high pressure switch to measure the oil pressure. If the pressure is normal, then the block from the cylinder to the cylinder head blockage; if the pressure is not normal, and below the specified value, you can check from the following aspects:
    1. Check whether the oil is diluted, because the oil is too thin will make the oil pressure down, if the oil is dirty, you should replace the oil and oil filter;
    2. The general driving more than 80,000 km of the car, maintenance should be cleaned and check whether the deformation of the oil pan, oil pump filter is blocked;
    3. Check and clean the oil pump, clean the pressure control valve, check the pump fuel supply, gear pump gear wear limit of not more than 0.7mm, axial wear limit of not more than 0.5mm;
    4. Check the crankshaft main pad gap, the ultimate wear does not exceed O.17mm, check the connecting rod tile gap, the ultimate wear does not exceed O.12mm check the middle shaft radial clearance, should not exceed 0.25mm, check the camshaft clearance, the maximum does not exceed 0.1mm;
    5. Clean and check the oil, after repair the oil pressure should be more than 3.5bar in order to normal use.