4 Symptoms Of A Faulty Engine Oil Level Sensor

The oil level sensor measures oil levels in the oil tank, much like how the fuel level sensor monitors fuel levels in the fuel tank. 

This device protects the car’s engine by notifying the driver of rapid oil loss or an oil leak. It also indicates when the engine needs an oil change and monitors the oil pressure and the oil level. 

Knowing when you have a faulty oil level sensor helps prevent unnecessary damage to your engine. Here are the most common signs: 

1. Inaccurate Oil Reading

A faulty oil level sensor may trigger incorrect ECU (Engine Control Unit) readings. This results in the oil level or low level warning light illuminating even when oil levels are normal.  

So how do you tell when your engine oil level sensor is not working? 

Here’s what you can do if your oil level warning light comes on:

• Check oil levels using a dipstick
• Monitor the oil pressure via the oil pressure switch
• See if your engine needs an oil change
• Look out for signs of an oil loss 

If your oil sensor light continues to light up despite everything being normal, it could mean your oil level sensor is malfunctioning. 

2. Oil Light Blinking Sporadically

The oil sensor’s function is to detect the oil level in the oil tank when the engine is off. 

If the oil light blinks sporadically or comes on after you’ve been driving for a while, it could point to a failing engine oil level sensor. This is usually caused by a faulty engine oil management system, which incorrectly triggers low oil levels or oil pressure warnings. 

3. Check Engine Warning Light Comes On   

Incorrect readings from the oil level sensor can sometimes trigger the check engine light on your dashboard. 

When the check engine warning light is illuminated, first, ensure that your oil pressure, engine temperature, and oil levels are normal. You should also make sure the oil is clean, and there is no obvious oil leak in the engine (like a little oil puddle under your car).   

Nonetheless, an illuminated check engine light can signify many things, so it’s best to have the oil sensor and the oil pump checked by a reputable mechanic. 

4. Vehicle Not Starting

The oil level sensor is responsible for sending warning signals to the ECU (Engine Control Unit.) 

However, a faulty oil level sensor or oil pressure sensor may detect incorrect oil readings. 

Sometimes, when the oil level sensor is not working, it might send incorrect codes to the ECU. This causes the ECU to cut off the ignition and fuel, preventing your engine from starting up.

In this situation, your mechanic will need to download the error code, pinpoint the actual problem, and perhaps replace the oil level sensor.

How Much Does An Oil Level Sensor Replacement Cost?

The cost for an oil level sensor replacement varies according to the make and model of your vehicle. 

Typically, the total cost ranges between $121 to $160, which can be broken down into: 

• Labor costs: Approximately $73 to $93
• New parts: Roughly $48 to $67

How Critical Is An Engine Oil Level Sensor Replacement?

Motor oil plays an extremely important role in keeping your engine running smoothly. 

However, a faulty oil level sensor makes it difficult to determine any oil issues, resulting in an undetected low oil level and increased engine temperature. 

When your oil level is low, critical engine components won’t receive sufficient lubrication, causing friction between them. If left unresolved, you could end up severely damaging your engine with potentially costly repairs. 

So it’s best to get a new oil level sensor as soon as you can.

3 Oil Level Sensor FAQs

Let’s look at three common questions around the oil level sensor and their answers:

 1. What Is An Oil Level Sensor?

The oil level sensor is a device that monitors the liquid level in the engine oil tank, ensuring your engine has enough oil and runs smoothly. Its job is to alert you if there’s a low oil level or even little oil leaks.

The sensor measures motor oil levels in a dynamic range (when the engine is running) and a static range (when the engine is off). 

Now, let’s take a look at the four different types of oil level sensors:

• Mechanical sensors: The mechanical oil level sensor has several common applications. In these oil level sensors, the switching occurs when the float switch (within the sensor) moves against a micro switch at actuation levels or through magnetic operation. Float-style mechanical sensors aren’t suitable for high viscosity oils. 
• Pneumatic sensors: This sensor is a relatively low-cost technique for point level monitoring in a lube system best suited for hazardous conditions. Here, the process liquid makes no contact with the sensor’s moving parts and instead uses a column of air against the diaphragm to actuate the switch. 
• Ultrasonic sensors: The ultrasonic sensors are non-contact liquid level sensors that can sense highly viscous liquids and bulk solids. These sensors comprise a single multi-chip module integrated with a pressure sensor, temperature sensor, and an ASIC (Applications Specific Integrated Circuit.)
  
  This device has greater shock and vibration resistance and uses acoustic waves to measure the liquid level of oil and even hydraulic fluid. 
• Conductive sensors: Conductive oil level sensors are ideal for point level detection of highly corrosive liquids like hydraulic fluid or caustic soda. While this type of sensor isn’t a very popular choice for oils (as oils typically have an insulating property), we’ve included it since many conductive liquids are on the market.  

2. What Causes An Oil Level Sensor To Go Bad?

The following are the most common reasons why an oil level sensor might not function properly: 

• An internal short circuit
• Sensing elements failure
• Sensor electronics failure
• A missing voltage or ground connection
• Potential oil leak through damages in the sensor housing

Apart from this, factors like climate, or driving habits, can also affect the overall health of your engine’s oil system in general.

3. How To Replace An Oil Level Sensor?

Replacing a bad oil level sensor with a new sensor is complicated and time-consuming. So, if you’re unfamiliar with DIY repairs, you should contact a reputable mechanic. 

That being said, here’s a brief guide on replacing the oil level sensor: 

1. Jack up the vehicle using factory-recommended jacking and standpoints.
2. Now place the wheel chocks on both sides of the wheels.
3. Next, locate the oil level sensor (besides the oil pan or at the bottom of the oil pan)  with the vehicle properly raised.
4. If it is placed at the bottom of the pan (facing upward), you’ll need to drain the engine oil. Otherwise, place a drain pan below the oil level sensor to collect the oil leak.
5. Next, unfasten the electrical connector from the oil level sensor.
6. Proceed to remove the oil level sensor along with the oil filter, gaskets, and o-rings. Ensure that the replacement oil level sensor has the same dimensions as the old one. 
7. Clean the area around the oil level sensor mouth to get rid of any dirt or debris. 
8. Position the new sensor correctly, and tighten it with a wrench. 
9. Next, you’ll need to reconnect the electrical connector.
10. You can now remove the jack stands and refill the engine oil.
11. Finally, start the engine and let it run for a few minutes. Look for any potential leaks and ensure the oil is leveled.