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The oil pressure light comes on at idle: troubleshooting and troubleshooting
The oil pressure light comes on at idle: troubleshooting and troubleshooting

There are several types of malfunctions that make motorists sweat. One of them is the low pressure alarm in the lubrication system. The question immediately arises: is it possible to continue driving or do you need a tow truck? There are several reasons why the oil pressure light comes on at idle. They do not always talk about a serious breakdown.

Pressure drop due to leaks

Often, the cause of low pressure can be identified long before the warning light appears on the dashboard. If the car is not old and has low mileage, the pressure will directly depend on the oil level in the lubrication system. The first thing that pressure drop indicates is oil starvation.

Few car owners regularly look under the car for oil leaks. The appearance of spots on the asph alt under the car is a cause for concern.

Reducing the oil level in the sump

It is normal to add oil to the engine between replacement cycles. Each motor has a lubricant consumption rate. But if the flow goes beyond them, then you need to find the reason.

The external inspection of the parking lot of the car, as well as checking the level, must be introduced into constant practice. However, there are reasons why the oil pressure light comes on at idle, regardless of the amount of lubricant in the crankcase. This can indicate both a malfunction of certain elements of the lubrication system, and engine wear.

Why does the oil pressure light come on

The lubrication system has many parts, all of which can affect pressure. Consider the main elements:

  1. Engine pan. This node is a container containing oil. The dipstick inserted into the engine shows the level in the sump. A leaky gasket between the crankcase and sump contributes to oil leakage. The drain plug may also be leaking. After changing the oil multiple times, the thread tightness may be compromised.
  2. Oil pump. Its main malfunction is mesh clogging. It is designed to protect the system from large wear particles that accumulate in the sump. When the engine is cold, the oil is thicker and more difficult to pass through the screen. The pressure is low. As the lubricant warms up, more is supplied, and the sensor stops signaling low pressure. Therefore, the screen must be periodically cleaned during maintenance.
  3. oil pump
    oil pump
  4. Oil receiver. This partthe oil pump can be damaged if the bottom of the engine hits an obstacle. This results in pallet deformation that is difficult to determine visually. In this case, the oil pressure light is flashing because the pump is not drawing enough lubricant.
  5. Oil filter. One of the tasks of this element is to maintain pressure in the lubrication system after the engine has stopped. The filter has an anti-drain valve that prevents oil from draining into the sump. This is necessary so that during start-up the engine does not experience oil starvation. If the anti-drain valve of a cheap filter does not hold enough pressure, then the oil pressure light comes on at idle and stays on until the engine picks up speed.
  6. Reducing valve. It is designed to automatically control the pressure in the lubrication system. It can be either assembled with an oil pump or be a separate element. Its failure also leads to a decrease in pressure in the oil line.
  7. Oil pressure sensor. If it fails, it may cause the warning light to go off falsely.
  8. Oil pressure sensor
    Oil pressure sensor
  9. Oil lines. Their clogging can occur due to the use of low-quality lubricants, failure to meet the deadlines for changing oil and filters. In addition, a service change to a different type of oil without first flushing the engine may render the lubricant unusable. For example, when switching from semi-synthetic to mineral oil.
  10. Worn crankshaft oil seals often lead to leakage,causing the oil level to drop.

How to check oil pressure

If the oil pressure light comes on at idle, the first thing to do is to check the operation of the pressure sensor. This error occurs frequently. It is easy to diagnose.

First you need to inspect the chips that connect the sensor. It happens that oxidized contacts do not transmit an electrical signal well. Before checking the oil pressure sensor, before starting the engine, you need to see if the pressure lamp on the dashboard is on with the ignition on. If it is not lit, then there may be a problem with the sensor contacts.

The second step is to unscrew the sensor. For this, a 24-mm open-end wrench is used. Some models of machines have two sensors. In this case, the verification is carried out sequentially. Screw the manometer adapter into the hole. After that, start the engine. Normal idle pressure is different for each engine. Mainly 2 MPa at 700-900 rpm and 4.5-7 MPa at 2000 to 2500 rpm.

oil pressure gauge
oil pressure gauge

If, when checking, the pressure gauge shows normal pressure when the engine is idling, as well as under load, then the sensor needs to be replaced.

Using the “wrong” oils

There is a saying among motorists that the inconsistency of engine oil with a particular type of engine can lead to serious damage. How true is this?

The main criterion for oil isviscosity. On canisters, it is indicated by the letter “W”. The first digit before “W” indicates the viscosity at low temperatures. The lower the number, the colder the engine can be started without the risk of lack of lubrication on the rubbing surfaces.

engine oil
engine oil

The second number indicates the viscosity when the engine is warm. The temperature of the oil in the lubrication system reaches 100-150 °C. The more technologically advanced the engine, the lower the viscosity should be when heated. Each manufacturer in the service book of the car indicates the required oil viscosity.

Don't assume that more expensive oil is better for the engine. The main criterion is the requirement of the manufacturer.

Dependence of oil viscosity on engine wear

As the engine wears and clearances increase, it is recommended to switch to cheaper types of oils. For example, go synthetics to semi-synthetics. The operating viscosity will decrease, which will increase the oil film in the parts interfaces.

It happens that after changing the oil, the oil pressure light is on. Sometimes this is due to a change in the type of oil, when the old one is not completely drained and it conflicts with the new type. Then the grease from a liquid state can turn into a grease and clog the oil lines.

However, it often happens that a new oil filter is to blame. To find out the cause of the malfunction, you need to change the filter and see if the pressure lamp goes out. If not, then you need to open the engine filler neck and, with the engine running, find out if the oil rises to the valve cover. If ano, the problem is with the oil pump.

Dependence of pressure on the level

Another reason why the oil pressure light comes on at idle is a low level. During the change, the oil does not drain immediately due to its viscosity. Therefore, in order to correctly determine the level, you need to wait 5 minutes.

oil dipstick
oil dipstick

How do I know how much oil to change in the engine? There is an indirect method: fill in the same volume as was drained. But this method has an error. The engine itself consumes lubrication during operation. To correctly determine the required amount of oil, you need to focus on the marks on the dipstick. You need to fill up to the top mark. From one change to the next, the oil level may drop from the top mark to the bottom. If it goes more than normal and the oil pressure light comes on at low speeds, then this indicates problems associated with engine wear.

When the pressure light does not indicate a malfunction

After turning the key, the oil pressure lamp lights up in the ignition lock.

oil pressure lamp
oil pressure lamp

This indicates that there is currently no operating pressure in the system. After starting the engine, the light may not go out for several seconds. This happens for several reasons:

  1. Thick oil after a long stay. It slowly fills the lubrication system. To avoid this effect, it is preferable to use synthetic and semi-synthetic oils.
  2. First of all, grease is filledmain and connecting rod necks. Only then does the oil reach the sensor, and it starts to show pressure.
  3. Strong roll of the car when driving. In this case, the light begins to blink, because the centrifugal force takes the oil away from the oil receiver, and it cannot suck in enough lubricant. Therefore, dry sump is used for cars that constantly drive in sport mode.

Engine wear and pressure booster additives

In recent years, a new kind of automotive chemistry has appeared on the shelves - additives to increase oil pressure and engine compression. If there is wear on the parts, is there any point in using them?

The work of additives is aimed at restoring the initial dimensions of worn parts, as well as improving the oil-retaining ability of rubbing surfaces.

oil additives
oil additives

A significant reduction in oil consumption was noted with the use of such products as "Rimet", "Suprotek". The service life of the engine before overhaul was also increased.

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