In any modern car, the oil system is one of the most important aspects of the longevity and reliability of your vehicle. It keeps your engine lubricated and cooled so you can keep driving without melting and smashing parts of your engine. Except, what happens when your oil pressure is too low or high?
A bad oil pressure sensor will not alert you when your oil pressure is at dangerous levels. It can result in driving too far with not enough oil. As a result, your engine can seize and weld itself shut, and your car will likely be totaled. It is very dangerous to drive with a bad oil pressure sensor.
This is the main job of your oil pressure sensor: it alerts you if your pressure is out of the perfect operating range. In this guide, I’ll be explaining more about this sensor, and how dangerous it is to drive with a bad oil pressure sensor.
How Your Oil System Works
You probably know that your car uses oil, but how exactly does it work? Plus, what’s the point of oil in the first place?
The oil’s purpose is to lubricate parts of your car and help keep things cool.
Oil sits in a pan in your car, and a pump will move it around and circulate the oil. It actually works a lot like blood going from your heart to the rest of your body.
The oil will go through your engine, lubricate the moving parts, then pass through a filter and go back to the pan. It’s a closed system. This means that new oil is never introduced until you change your oil.
Why Oil Pressure Matters
I’ll be talking about oil pressure sensors, but I should talk about oil pressure in general first. The pressure of your oil will allow it to move in the first place.
As I mentioned, oil gets pumped around your car so it can lubricate moving parts in the engine. Without pressure, oil would just sit in the pan forever and not move.
Oil cannot be correctly pressurized if there’s a leak in the line, a clog, broken components, or the oil pump isn’t working at all. Suddenly, the oil can’t pump. Parts won’t get lubricated or cooled down, and you can run into a lot of problems.
What Is an Oil Pressure Sensor?
The oil pressure sensor is installed to avoid this issue. The sensor itself is a really smart piece of technology.
Simply knowing the pressure of your oil is one thing, but knowing when it hits a critical value is a completely different challenge.
Engineers developed a small system that your oil sensor checks. It has an inlet for oil to enter this small system, then a diaphragm plate with a few springs suspending the top part of the plate. Under the top plate is a sensor, a little bit away.
When everything is running well, the oil will push against the bottom plate and keep the assembly suspended. This creates a gap between the top plate and the sensor under it.
When your oil pressure starts to dip, then both plates start falling down. When the pressure isn’t high enough, then the top plate will come in contact with the sensor and trigger your “oil pressure” indicator.
The same exact system also works for oil pressures that get too high — this is the genius behind the system.
In other words, if your oil pressure isn’t in the perfect operating range, the sensor will get triggered, and you’ll see a light on your dashboard.
The Purpose of Oil Pressure Sensors
The only purpose of an oil pressure sensor is to tell you if your oil pressure is too high or too low.
If it’s too high, then you risk something bursting. It also means that the oil will flow too quickly and won’t be able to correctly cool and lubricate engine parts.
If the oil pressure is too low, then it can’t appropriately flow through your engine. It might not be flowing at all.
In either case, your engine won’t get the optimum level of lubrication and cooling. This can lead to extensive damage under your hood and can total your vehicle through a seized engine.
Oil Pressure Sensor Vs Oil Pressure Switch
An oil pressure sensor and an oil pressure switch are two different devices that are used to monitor the oil pressure in a vehicle. An oil pressure sensor is a device that measures the pressure of the oil in the engine and sends this information to the vehicle’s computer system.
The computer system can then use this information to adjust the engine’s performance or to alert the driver if there is a problem with the oil pressure. An oil pressure switch, on the other hand, is a simple on/off switch that is activated when the oil pressure reaches a certain level.
When the oil pressure falls below this level, the switch will turn off, which can trigger a warning light or an alarm to alert the driver. The oil pressure switch is typically used as a backup to the oil pressure sensor and is typically less accurate than a sensor.
Symptoms of Low Oil Pressure
Low oil pressure comes with a few different symptoms. Here are the more common ones to look out for.
Your Oil Pressure Light Is On
The first indicator of low oil pressure is that your oil pressure light will turn on. When the light turns on, it’s typically an emergency and you should pull over immediately to fix the issue.
Every mile you drive while your light is on is a risk.
A Clunking Engine
Without proper lubrication, your engine will start grinding and banging. This will feel like something clunking in the front of your car. This is a really bad sign, and it means that the damage is already starting.
Engine Is Overheating
One of the more silent issues to carefully monitor is the engine overheating. This can happen when there’s a little bit of oil flowing through the system, but not nearly enough.
There are some signs of an engine overheating, but the biggest one is that the temperature gauge will go to the red area and an alarm might go off.
You Smell Something Burning
A burning smell is typically a good reason to start panicking in your car. In the case of low oil pressure, the burning smell could be due to a broken, cracked, or failed gasket. Oil might be leaking from this gasket and burning up in your engine bay, which gives off that burning oil smell.
Is It Dangerous to Drive with Bad Oil Pressure Sensors?
If you have a bad oil pressure sensor, one of two things is happening: either the indicator light is always on, or the light will never turn on. In either case, driving with bad oil pressure sensors is very dangerous for the engine and can lead to very expensive repairs.
The sensor is there to protect your car and give you a heads-up if something’s wrong. With a faulty sensor, there’s no way to tell for sure.
Sure, you can use the other symptoms of low oil pressure to tell if your oil pressure isn’t perfect. But the stakes are so high when it comes to oil pressure. When you start noticing the other symptoms, it’s often too late and there has already been damage associated with the oil pressure.
The best option is to have a functioning sensor that gives you a heads-up ahead of time.
What Causes Low Oil Pressure?
Low oil pressure can be the result of a few big issues. As I mentioned, your oil system is a closed loop. If anything opens that loop or prevents its flow, then your oil pressure will suffer.
Oil Pump Failure
One of the more catastrophic failure modes is through a failed oil pump. If the pump can’t operate, then it can’t facilitate the flow of your oil. The result? An engine that doesn’t get any lubrication or cooling.
An oil pump failure is one of those problems that you simply cannot ignore. Driving too far with a broken oil pump will result in extensive damage to your engine — the most expensive and important part of your vehicle.
Oil pumps can fail due to age, damage, or any list of issues. Troubleshooting the pump can be a little tricky. To fix it, you’ll need to replace the full pump with a new OEM version.
Clogged Oil Filter
Oil filters can also restrict the flow of oil through your system. This is more common as you get closer to when you should change your oil.
By the way, make sure you’re always changing your oil filter whenever you change your oil.
The filter is there to screen out any debris and particles that could damage your engine. After all, the oil is going through the engine. If a piece of metal is lodged in the oil and gets into your engine, it can wear out parts and break them down.
Over time, the oil filter will clog with debris that is filtered out. When enough debris is trapped in the filter, there won’t be enough space for the oil to freely flow. It will restrict the flow, drop the pressure, and lead to reliability issues.
Not Enough Oil
If you don’t have enough oil, the optimum pressure can never be reached. A lack of oil can be the result of a few different problems:
- Leaking gaskets. There are rubber gaskets between different surfaces that will make a sealed connection. If the gasket has any cracks or damage to it, oil can squirt out and slowly leak from these connections. Since oil isn’t routinely added, this will make your oil level drop slowly over time.
- Improper maintenance. Some people simply don’t know how much oil their car needs. If you underfilled your oil pan in a recent oil change, then there’s a chance your system is too low to pressurize. Check my guide to learn how to change your oil.
- Damaged lines. If there is rust, mechanical damage, or failing connections between any lines that are used to move oil around, then the oil can leak. After parking overnight, back out of your spot and check if there are oil stains under your car. This is a sign of damaged lines which will deplete your oil level.
Your oil pressure sensor does a lot of heavy lifting for something that isn’t talked about a lot. It will prevent massive damage to your car, so it’s best to have an operating oil pressure sensor at all times. Using a broken sensor can result in you driving with low oil pressure and not even knowing it.