Why does the oil pressure lamp light up on the car dashboard

What to do if the oil pressure lamp lights up In case the oil pressure lamp lights up, it is necessary to stop the car, because driving with such a warning can be dangerous

The oil pressure indicator on the dashboard of the car has a red color and its illumination means danger, like a red traffic light, and definitely requires stopping the car. The main questions motorists should know the answers to – this is for what reason the oil pressure lamp can light up and what should be done to eliminate the malfunction.

Structurally, the lamp light is designed for a drop in pressure in the system of less than 0.4 kg/cm, which signals the absence of oil pressure in the line and the beginning of semi-dry friction of all the responsible connections of the engine.

Since oil, in addition to its lubricating properties, is also responsible for heat removal from the mating parts, the drop in pressure will sharply increase their temperature, and the condition of the engine will quickly approach critical. In addition, overheated oil will dramatically lose its properties and will not be able to keep the oil film (oil wedge) between the rubbing pairs even when the speed increases.

There can be several reasons for the oil pressure drop, let’s consider the most common ones: – Oil of inappropriate viscosity was filled; – Dirty oil that served to open the bypass valve in the oil filter; – Extreme wear of the oil pump; – Crack in the oil intake of the oil pump or its flange; – Failure of the pressure reducing valve; – Problems in oil pump actuator; – Severe wear of crankshaft main bearing shells; – Scoring of main bearing shells due to insufficient clearance during assembly; – Oil pressure gauge defect; – Oil level in engine sump below minimum mark. How to eliminate the fault?

If you use low-quality oil from an unknown manufacturer, the oil pressure indicator lamp may light up, because the oil is unable to keep between the crankshaft journal and the liner (oil wedge breaks). The oil must be changed to the viscosity grade prescribed by the manufacturer.

Opening of by-pass valve in oil filter is connected with strong oil contamination, when filter element is clogged so much, that it is no longer able to pass oil, and untreated oil flows through the valve to friction units. This is a forced measure, because if the bypass valve is not opened, the engine will be left without oil at all and will jam in a few minutes. It can be eliminated by changing the oil and the oil filter with the obligatory flushing at the new oil filter with its subsequent replacement and filling with the new quality seasonal oil.

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When the operational wear and tear of the oil pump reaches the maximum allowable standards, it can no longer provide the necessary pressure in the system. The pump must be either repaired or replaced.

If there is a crack in the oil intake or its flange, the pump starts to trap air and an air lock prevents the oil pump from generating a certain pressure. It can be repaired by replacing the damaged parts or by welding with argon.

Failure of pressure reducing valve can be caused either by a foreign object getting under its ball or by unprofessional assembly when it is left open. The defect can be corrected by cleaning, properly assembling and installing the valve and adjusting it.

The oil pump can have different types of drive depending on its design: direct drive – when installed on the “toe” of the crankshaft (most modern engines with a belt in the timing belt drive); via an intermediate shaft (popularly “piggyback”) via the splined connection (in classic VAZ models, the so-called “mushroom”), via a chain (BMW engines) and other less common ways.

The crankshaft sock drive has practically no disadvantages, since the oil pump is “seated” directly on the crankshaft tab and the pump can only stop operating due to the crankshaft stopping. When the drive is via the intermediate shaft, the connection is made on splines (with a fine pitch), which are subject to wear. The splines can be worn on the oil pump shaft as well as on the actuator (“mushroom”). With minor wear the pressure lamp starts blinking, and when the splines “cut” completely the lamp lights up at full intensity. It can be eliminated either by replacing the oil pump shaft, the oil pump itself, or (in most cases) by replacing the “fungus”. Chain drive oil pump, as a rule, is adjusted by the chain tension, in cases of its high slack from excessive wear, pressure drop and lighting of oil control lamp is possible. Can be corrected by replacing chain or adjusting chain tension.

The oil pressure gauge light may be caused by excessive wear of the crankshaft main liners, when the gap between the liner and crankshaft journal can no longer hold the oil “wedge”. This can be eliminated by disassembly of the engine by grinding the crankshaft to the next repair size and installing new main bearing shells of the same size.

To “wait” till the overhaul and not “knock out” the next overhaul size (that will immediately reduce the crankshaft life), it is necessary to buy oil of a higher viscosity. In this case you should avoid using diesel fuel oils, like MS-20 (which so many motorists like: they say is cheap and sulfurous), because they contain a lot of sulfur, which can transform into sulfuric acid, damaging all engine parts. Any oil sales centers have so-called “problem oil” that has a higher viscosity but is designed specifically for car engines.

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Scoring on the crankshaft main liners leads to a drop in oil pressure, which is caused by unprofessional assembly – small clearances during assembly. Rapid wear of the main liners can also be caused by poor quality crankshaft repairs, when the relative runout of the main journals exceeds 0.07-0.10 mm. This also causes the oil pressure to drop.

If the oil pressure gauge light comes on, it may be due to a faulty pressure sensor. Checked with a mechanical sensor for actual pressure in the engine. Remedied by replacing the sensor.

The oil pressure warning light may also be illuminated by excessive oil consumption (or leakage), when the oil level “drops” below the “minimum” mark and the oil pump intake cannot take in the required amount of oil. The same thing happens at a tight corner when there are no baffles in the sump to prevent the oil from “rolling” when the car rolls. An example is the first ZAZ 1102 Tavria, where in the service manual it was stated that the pressure control lamp could light up for a short time. Later, baffles were installed and the defect disappeared.

Whatever the reason for the oil pressure control lamp to light up, the driver must immediately stop the car and try to find out the cause. If you can not fix the problem on your own, the car should be towed to the nearest service station, as the movement with a lit lamp is dangerous and can lead to jamming the engine.

Oil pressure light illuminated

All experienced drivers know that if the oil pressure lamp lights up, it is necessary to immediately take the necessary measures. The icon should appear when you turn the key to position II, but immediately disappear after starting the engine. If it flashes at idle, in motion (revs medium, high) – this is already a malfunction and it is necessary to find out why it happens.

Why do you need an oil pressure indicator lamp?

The indicator is needed to timely notify the driver of problems with the lubrication system of the car. Without the oil pressure light, it’s hard to guess that the engine is running in oil starvation mode. And the danger is that a crankshaft, camshaft, timing mechanism, liners and other units (parts) of the engine are completely destroyed in this case for a short time.

Oil pressure gauge on the dashboard

Oiler Icon on the Dashboard

The red indicator is a mandatory element of the dashboard, installed at the production stage of the car. In new systems the oil sight glass is normally integrated with a sensor and lights up (continuously lit or flashing) when the engine is running, if the oil pressure value falls or rises. Here you can not delay, you must urgently shut down the engine to avoid “knock” – the spell of the power plant, when you can not avoid overhaul or complete replacement of the internal combustion engine.

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The main reasons of indicator lighting up

The control lamp lights up due to various factors, it is not always related to lubrication. Below are the main reasons for the oil light to light up on the dashboard. Let’s take a closer look at each of them.

Low grease level

The engine fluid should be checked regularly. Even on new engines, the grease burns out during active vehicle operation. And if the powertrain is old, worn drives take in several times more oil. Therefore, it is extremely important to periodically remove the dipstick before a trip and look at the fluid level – if the amount is low, you need to refill it.

Checking the oil level with the dipstick

Checking the Lubricant Level with the Dipstick

The oil pressure indicator most often lights up in drivers who ignore the mandatory rules of car operation.

Autol also needs to be replaced in a timely manner.

When it is worn to the limit, the lubricant level will a priori drop along with the pressure. Therefore, at the 10-15 thousand kilometers mark it is advisable to drain the used fluid completely and refill it with a new one.

The third important rule is to use only good formulations, with the correct viscosity. If the lubricant is of poor quality, it will quickly lose its original properties during the operation of the engine. The thickness of the oil film will be insufficient to lubricate the internal combustion engine elements – it will be torn when accelerating, driving at high speed or overloading. This will cause dry friction with all the ensuing consequences.

Excessive fluid in the system

Excessive amounts of fluid also cause variations in pressure (in this case, an increase in pressure). This causes engine gaskets and seals to burst, as well as:

  • the timing belt breaks – in turbocharged engines (with high compression ratio) in this case it is ensured that the valves meet the pistons;
  • faster wear of crankshaft;
  • The filter suffers, quickly clogging from sharply increased quantity of impurities and deposits;
  • damage of electronics – control unit, sensors;
  • hydraulic pushers are destroyed because there is a lot of foam inside the unit.

Overfilling can be detected by the oil dipstick – the level is above the MAX mark. It is necessary to urgently get rid of excessive oil. To do this, the lubricating fluid must be pumped out.

Bleeding out the engine oil with a syringe

Pumping out the lubricating oil with a syringe

This can be done directly through the throat with a special vacuum pump or a large medical syringe. You can also do it through the drain, but then you need an inspection pit or a hoist.

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Usually oil goes from under different collars, seals, and cylinder-head gasket (more about it below). The engine has many gaskets, so leakage is not uncommon, especially on older units. In addition, the places of leakage of lubricating fluid are torn fittings and lines. The indicator light comes on as soon as the lubrication pressure drops, which a priori occurs when lubricant is leaking in large quantities.

The engine oil level gauge on the dashboard

Lubricant leakage

Poor filter

The main task of an oil filter is to clean the fluid entering the pump from foreign solid particles and deposits that accumulate in the crankcase sump of older engines. Poor-quality products quickly clog up and fail early. As a rule, their diaphragm blows, bursts or jams. Because of this, the oil pressure lamp constantly lights up.

Bad cleaners fail to cope with their tasks also because of the lack of a shut-off washer – a special check valve, thanks to which a fraction of oil always remains in the filter.

This is needed in order to provide lubrication when starting a cold engine, when the system is not yet ready – to provide it with lubrication.

Sensor failure

Modern cars use several sensors associated with the oil system. When they malfunction, the oil pressure light on the dashboard either lights up constantly or does not respond at all. It is necessary to check the regulators among the first ones, because most often they are the cause of incorrect operation of the indicator.

Oil level gauge

Lubricant level sensor

If the indicator does not turn off, most likely the level gauge slider is jammed or there is another failure. But the pressure alarm is more likely to go off in the winter, when starting the engine when it is cold.

Pump failure

The oil pump has a pressure reducing valve. It solves an important task – it regulates the level of the technical liquid, preventing it from rising or falling. When it malfunctions, the engine is subjected to oil starvation, and there is no pressure at all at any rpm.

The malfunction is usually caused by:

  • The valve spring – it is severely stretched or simply breaks;
  • clogging – occurs when the engine is filled with dirty, low-quality compound.

Naturally, when the automatic valve is damaged, the pressure in the lubrication system increases sharply, especially when the engine is under heavy load. Additionally, the pump fails due to broken or deformed gears.

Oil pump pressure reducing valve

Oil pump pressure reducing valve

Not uncommon is a clogged oil receiver. This happens quite often on machines where the engine is not protected from below by the factory provided cover. A few bumps with the pallet on the ground – and the problem is ensured. This element may also become deformed because of crankcase jamming.

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Wiring problems

Oil pressure light does not turn off also due to faulty wiring. Due to damaged insulation of individual cables, the indicator receives a false signal. But on many modern cars this process is monitored by the ECU, and in case of electrical short circuits it alerts the driver with the error code ELM 327.

If the ECU does not give a signal or does not work correctly, the wiring short circuit is checked in another way. Disconnect the wire from the alarm and connect it to any part of the car’s bare body. Oil pressure lamp does not light – wire is broken, insulation is damaged, dents are present.

Gasket breakdown

When the cylinder-head gasket punctures, engine grease mixes with antifreeze. The oil level rises sharply at the expense of coolant inflow. It is possible to detect an “uninvited guest” by a changed color of grease on the dipstick, a strong unpleasant smell from under the radiator cap or expansion tank. Also an oily film can form in a radiator. A punctured gasket must be replaced immediately! It is impossible to drive a car in such condition – the antifreeze will easily ruin your engine if it gets inside.

Oil level gasket punctured cylinder-head gasket

Punctured cylinder-head gasket

Effective ways to check

Usually, when the oil pressure light is faulty, a pressure gauge is used. With this tool, the pressure is measured. First, the engine is brought to operating temperature, then the gauge is unscrewed and the device is inserted instead. Then the power unit is started again. The indicator is tested first in neutral, and then at high revolutions.

Specialists can also determine by indirect signs, why the oil pressure light is lit.

  1. If the cause of the malfunction is the filter, the indicator will flash at idle and low revs. In most cases, the icon disappears if you press the accelerator pedal in neutral (increase revs).
  2. If the emergency lube level sensor is defective, the oil pressure light may also blink while the engine is running or not illuminate at all in activation mode.
  3. The pressure reducing valve is checked after the sensor is confirmed to be working.

The faulty sensor is usually replaced. But there is another variant of troubleshooting, without waiting for help – it is necessary to shake the connection, where the element connector is plugged. Such method will “revive” the sensor contact, if it is acidified. The filter – unequivocally install a new one. As for the reducing valve, the element is removed after dismantling the oil pump. If the valve is just jammed – you need to take it out, wash it in gasoline and be sure to lubricate it. Weak, stretched spring is desirable to immediately replace a new one, and clogged valve channels – clean.

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