Your engine, just like most other mechanical constructs that contain many moving parts within them, requires grease. In particular, motor oil, which most car owners should be more than acquainted with during their ownership. However, there’ll be times of trouble when that very same oil is the cause of heart-sinking issues. For example, noticing your car reading what is considered low oil pressure.
Engine oil is, of course, absolutely necessary in every engine-powered vehicle (any electric car being a noteworthy exception). Their role is wide-ranging, which is predominantly occupied with keeping the engine’s many moving parts lubricated. Thus, preventing these metal pieces from grinding onto each other. Moreover, motor oil also serves numerous other roles, such as cooling, or inhibiting corrosion.
Without sufficient lubrication, even the best engines could destroy themselves and implode within a few minutes. Hence, why everyone (yes, that also means you, reading this) must take good care of the motor oil. Not merely in the quality of the oil, but also regarding its circulation. That’s why it can be quite concerning when you’re spotting flow rates with what is considered low oil pressure.
- What Does Oil Do?
- Why Pressurise It?
- How Much Pressure?
- Fixes And Costs
- Final Thoughts
What Is The Function Of Engine Oil, And Why The Pressure?
While we’re discussing what is considered low oil pressure, a refresher would do us good. Primarily, it might prove pivotal for us to remind you why engine oil is such an important fluid. In layman’s terms, engine oil is a lubricating fluid that flows within your engine. By running through most of your engine, the oil leaves behind a thin greasy film atop any surface of components that it touches or flows past.
In doing so, those moving components can interact with one another smoothly, and without tearing or ripping the whole engine apart. Metal-on-metal grinding is a great way to scrap an engine within a matter of minutes, if not seconds. Therefore, the effect of using motor oil isn’t only related to your engine’s longevity, but could also ensure reliable performance, as well as optimizing fuel efficiency.
Besides These, Your Car’s Engine Oil Also Works To:
- Reduce Friction – Sticking oil to the inner surface of your engine and its many moving parts prevent it from wearing the engine excessively. Engine oil has a tendency to stick for long periods of time, which is especially useful for cold starts.
- Cleaning Impurities – Your engine can attract impurities from within, such as metal shavings, dirt, and so on. Motor oil can prevent this from causing damage to the engine by either keeping the impurities suspended in the oil, or not allowing them to adhere elsewhere.
- Engine Cooling – This is partly thanks to the oil reducing friction between the engine’s moving parts. It subsequently avoids the engine getting too hot. In addition, the oil can absorb heat from the engine’s many componentry, and circulate it away to be cooled down.
- Sealing – Being a liquid, engine oil could help provide a dynamic seal in the gaps within the engine. An example would be around the piston rings and cylinder walls. This seal ensures the combustion gases to be contained in the combustion chamber, aiding to maximize performance.
- Shock Absorption – As your engine’s moving parts oscillate, rotate, pivot, and whatnot, they naturally create mechanical shock in their movement. Oil, as viscous and greasy as it is, can help dampen that shock and disperse it over a wide area, lengthening your engine’s operational lifespan.
- Corrosion Resistance – Through the use of additives formulated into the oil, engine oil can minimize or outright prevent rust. It does this either by neutralizing corrosive impurities or creating a barrier that’ll prevent corrosion from forming inside the engine.
- Energy Transfer – Motor oil can’t be compressed. Thus, it has a great (somewhat hydraulic) ability to transfer energy. These are typically used in engines that adopt hydraulic valve lifters, or those that are fitted with variable valve timing systems.
Why Does Engine Oil Need (High Or Low) Pressure To Work?
As we look at what is considered low oil pressure, one has to wonder, why is it pressurized in the first place? Simply put, having fluids like motor oil be pressurized is a given. Pressure, measured in PSI (or pounds per square inch), builds up as your engine oil circulates through the engine’s many channels, openings, and gullies. If anything, noticing pressure is proof that your oil is even flowing at all.
If there’s too little or low oil pressure exerted to the engine, its meager flow can’t sufficiently grease up, cool down, or clean the engine. This includes key componentry such as the crankshaft, camshaft, pistons, bearings, and countless more in the path of the motor oil. Low oil pressure also denotes that your engine is being starved of oil, as only a small amount of it can circulate through the engine.
Similarly, engine oil pressure that’s too high is also a bad thing. The pressure increases as the engine oil encounter obstacles, which is otherwise normal. Nevertheless, too high of a pressure can lead to the oil flowing or skipping past narrower galleries. For instance, the bores or tiny openings for the oil to flow through. Consequently, overly high oil pressure will result in similar damage to low pressure.
In either extremity, they result in oil not adequately being spread out across the engine, which results in premature wear and tear. Not to mention, catastrophic engine failure altogether. In summary, the oil needs some degree of pressure to force it to pass through all of the engine’s key components. Yet, a bit too much or little pressure can have adverse effects on your engine’s wellbeing and performance.
What Is Considered Low (Or Normal, Or High) Oil Pressure?
Alas, engine oil pressure isn’t a constant shared across every vehicle. Certain makes and models carry higher or lower default oil pressure than others. Moreover, we also have to take into account several other variables such as the design and size of the engine. Factors such as the viscosity and type of oil, or even the operating temperature of the engine and oil could also require altering the oil pressure.
In other words, some cars work better (or at least, normally) at higher or lower oil pressure compared to other vehicles. As such, we’d highly recommend that you refer to your car’s owner’s manual to find the exact oil pressure quote under ordinary operation. From there, you could then better ascertain as to whether or not what you’re experiencing is what is considered low oil pressure.
Generally speaking, the average vehicle’s engine oil pressure should fall somewhere in between these figures:
- Normal – 25 to 65 PSI (this is roughly the ideal oil pressure range for most vehicles)
- Driving – 45 to 70 PSI (as the engine has to work harder when you’re driving, oil pressure will normally rise a bit more compared to its ideal readings)
- Idling – 20 to 30 PSI (during idle, the engine only has to keep itself cranking and turned on, so oil flow isn’t as greatly needed during this time)
- Too High – 80+ PSI (any higher than this reading tells you that the oil circulation is severely restricted to a point where it needs to push more vigorously to force the oil through)
- Too Low – Less than 20 PSI (figures less than this is a sign that oil is barely flowing into the engine at all, alerting you that lubrication and cooling is extremely limited at best)
Symptoms Why You’re Seeing What’s Considered Low Oil Pressure
Now that we’ve established what is considered low oil pressure, how can you notice them early on? It turns out, that you could very easily spot this much sooner, through the symptoms that low engine oil pressure can exhibit. The most notable ones include:
- Low Oil Warning Light – A sensor keeps a close eye on your oil pressure at all times. If it falls below or shoots beyond a set range, you’ll see a “Low Oil” warning appear on your dash. It’s worth mentioning that this light can sometimes appear only once the pressure drops to a mere 5 to 10 PSI.
- Check Engine Light – Low oil pressure can affect your engine’s operation in more ways than one. Your engine’s temperature might rise, as the timing chain adjuster (which is controlled by oil pressure) can malfunction. In either case, your car will warn you with a ‘Check Engine Light‘ alert.
- Odd Sounds – With minimal oil pressure and circulation, the engine’s moving parts are now bound to contact and grind against each other. This is noticeable with unpleasant rattling, knocking, clunking, ticking, or grinding noises emanating from the engine.
- Poor Performance – With little to no oil flowing into the engine, performance will suffer. It starts with a loss of power or poor acceleration. Sooner rather than later, you might experience rough idling, or stalling out in the middle of a drive.
- Burning Smell – Leakage may be the reason why you’re seeing a low oil pressure. At which point, you should be able to get a hint of burnt oil smell. This is usually due to engine oil leaking, and dropping onto a hot surface or component to burn itself out.
Causes Why You’re Noticing What’s Considered Low Oil Pressure
Seeing it drop to the low-teens or single-digit PSI is certainly what is considered low oil pressure, and alarmingly so. However, what’s prompting your car to go through this in the first place? How are you able to experience what is considered low oil pressure? Well, there are several root causes of low oil pressure that we can narrow down, which might help with troubleshooting and repairing them:
1. Low Level Of Oil (Either Oil Leaks, Or Burning Oil)
A vehicle’s engine oil is susceptible to losing volumes over time, but it shouldn’t occur naturally. Most commonly, your oil level will drop owing to a leak somewhere in the system. Or, your engine might be intended to burn through a lot of oil (i.e. excessive oil consumption) even in its regular use.
Regardless, a minimal amount of oil in the system will no doubt lead to lower oil pressure, as there’s less motor oil to go around. Moreover, a lack of oil can also lead the oil pump to draw in air from the oil sump. As the atmosphere rushes in and mixes with the oil under pressure, it can turn foamy.
This aerated engine oil is not only compromised in terms of its lubricating abilities. Moreover, it could cause oxidation within the engine. Without sufficient oil, your oiling system will struggle to pressurize what little there is to thoroughly circulate through your engine and lubricate it.
2. Using The Wrong Grade Or Viscosity Of Oil
Motor oil isn’t all the same, as different formulations of oil have varying viscosities. These are made for distinct types of vehicles, scenarios, and engine types. Anyway, using the wrong viscosity of motor oil that wasn’t designed for your engine might lead to low oil pressure, especially during idle.
In basic terms, we can distinguish oils into low viscosity and high viscosity. Low viscosity oils typically create less resistance as it’s more liquid-like, which means lower oil pressure. On the flip side, higher viscosities of oil are thicker, which requires more pressure to circulate them around.
Viscosity needs to be picked based on your use case. For example, the temperature is a major variable in how oil pressure builds. Usually, colder climates call for lower viscosity oil, as more viscous oil might be too thick to work in chillier weather. On the contrary, hotter climates necessitate thicker oils.
There are also multi-grade oils that could perform well in any season, regardless of the temperature outside. Still, we’d strongly recommend that you double-check your owner’s manual to gauge what viscosity and grade of oil have been optimized for use in your engine.
3. Faulty, Failing, Or Clogged Oil Pump
The oil pump is what’s responsible for circulating and forcing motor oil to flow around the engine. If it fails, no oil is circulated through the engine, and thus, your oil pressure reading will start to drop. It can wear or burn out over time, which can only be fixed with a full oil pump replacement.
Nonetheless, there are situations where the oil pump isn’t defective but merely clogged up with dirt and debris from the oil pan. Situated at the very bottom of the oil pan, the oil pump has a mesh filter that prevents impurities from getting picked up. However, this filter can clog up right quick.
When that happens, contaminants will start flowing into the oil pump and clog it up. As a result, the flow of clean and fresh oil is strangled, and your oil pressure will start cratering. Clogging can happen since the oil filter is situated after the oil pump, as the latter is lubricated purely with unfiltered oil.
4. Too Much Engine Oil Sludge Or Impurities
As motor oil ages and picks up countless little impurities and debris, as well as wearing itself down on top of being exposed to intense heat, can turn into a thick sludge. These clumps are the reason why a habit of regular oil changes is vital, as they can clog up key channels that prevent oil from flowing.
Sooner or later, oil pressure will fall in line with the reduced circulation. Most commonly, this sludge will build up around the oil filter, further putting a chokehold on the flow of motor oil to and from the engine. Eventually, the oil filter will get clumped up completely, forcing no oil to go past it.
5. Clogged Oil Filter And Bad Pressure Relief Valve
Speaking of, the oil filter naturally creates a resistance in the oil flow to filter out any unwanted grit or debris from entering the engine. This resistance will only grow as the filter ages, and impurities are piling up by its filtration nets. When this happens, the oil will struggle to flow through.
Hence, it would lead to a drop in oil pressure within the engine. Unfortunately, that pent-up oil flow in the filter will lead to higher pressure there. This can be alleviated with a pressure relief valve. Yet, and if this relief valve were stuck completely open, the oil pressure would drop by too much.
6. Worn Down Engine Bearings And Internals
Fun fact, the oil pump isn’t at all responsible for pressurizing the motor oil. This pressure comes from how fast it flows, and what resistance is in the way. Therefore, more resistance (or less clearance in the engine), means higher oil pressure. More specifically, clearance between the bearings.
In higher mileage or well-used engines, its inner bearings are likely to have worn down to a point that the once tight clearances in the engine are opened up. With larger openings and channels to circulate through, oil pressure will subsequently encounter less resistance, and keep on dropping.
7. Defective Oil Pressure Gauge Or Sensors
It’s quite possible that your car isn’t undergoing what is considered low oil pressure at all. There have been cases where it’s the oil pressure gauge or electronic sensors that are at fault. If the sensors are broken, false readings are sent to the ECU, which incorrectly brings up a “Low Oil” warning.
Or, perhaps the sensors are reading the PSI right, but your car’s oil pressure gauge is wonky. It might show you a higher or lower oil pressure reading than what’s actually going on. The only way to know if this is true is by connecting a pressure gauge directly to your car’s oiling system.
8. High Engine Temperature (Or Overheating)
Remember how we mentioned that oil pressure can swing wildly with how hot its surroundings are? Well, you might be experiencing low oil pressure for that very same reason. When your engine gets a bit too hot or is overheating, it can cause the motor oil to start thinning.
Even the most viscous oil types can thin when subjected to higher temperatures. When your oil starts to thin, it flows far too easily with minimal resistance. Therefore, this results in lower oil pressure, as though you topped up your engine with the wrong oil grade. It gets worse if it overheats, too.
Fixes (And Costs) To Solve What Is Considered Low Oil Pressure
With those respective problems in mind that can result in your car reading what is considered low oil pressure, how can we solve them? Here are a few solutions in mind:
- Oil Change ($50 to $200) – The most common culprit of low oil pressure is dirty and worn-out oil. This can be remedied with a quick and easy oil change for a fresh batch of fluids. It’s always a good idea to swap out the oil filter (including in the price mentioned) when you’re changing the oil, as well.
- Oil Flush ($100 to $150) – An oil flush can be considered a more thorough version of an oil change. It’s suitable if the gunk and sludge in your engine are too substantial for an oil change to dislodge. Flushing entails deep cleaning the oiling system, but is otherwise similar to an oil change.
- Oil Pressure Sensor ($50 to $250) – This usually comes in a pair with the oil pressure gauge, as well. A replacement is relatively inexpensive, with spares available for the low tens of dollars. Depending on your car, it could take as little as just 30 minutes to swap it out.
- Pump Replacement ($200 to $1,000) – Oil pumps by themselves aren’t terribly expensive, which could cost as little as $100. However, the process of replacing them is incredibly labor-intensive. This could easily outstrip the cost of the parts, and in some cars, the cost could total up to $2,000 or more.
- Engine Rebuild ($2,000 to $3,000) – If your engine’s bearings and innards are worn down, the only fix would be a full rebuild. This would be inevitable if your engine is too high mileage or is old. Rebuilding isn’t cheap, and could easily cost you several thousand to replace and recondition individual parts.
Understanding Low Engine Oil Pressure
- Oil pressure is a crucial engine parameter, and low pressure can indicate a major problem. It is essential to turn off the engine when the oil pressure light comes on or the gauge reports a lower-than-normal reading.
- Low oil pressure can be caused by a variety of factors, including not enough oil in the engine, a viscosity that is too high or low, and engine wear.
- Apparent low pressure in diesel engines may result from lubricants with lower viscosity. Lubricants can also affect oil pressure by generating higher or lower pressures.
- Pump wear or a plugged filter can also lead to low oil pressure. In the case of a worn pump, the engine must be stopped and the pump replaced.
- To reduce the risk of low oil pressure, it is essential to change the oil and filter at the correct intervals, use high-quality lubricants, and inspect the engine for leaks regularly.
- The oil pressure is essential to keep the engine lubricated correctly, and lubricant starvation can lead to metal-to-metal contact and machine failure. The viscosity of the oil affects the oil pressure, with higher viscosity leading to slower lubricant flow.
- The viscosity of engine oil depends on the ambient temperature, and SAE International developed viscosity grades to simplify the process of selecting the right lubricant for engines. SAE grades contain a minimum and maximum viscosity limit, with lubricant manufacturers formulating their lubricants within this accepted range.
Final Thoughts On What Is Considered Low Oil Pressure
Well then, that rounds up our look at what is considered low oil pressure. As you can recall, anything lower than 20 PSI can be considered as low oil pressure, which should be attended to promptly. If it’s patched up right away, you might be able to prevent quite serious internal damage and premature wearing with the engine. That alone will keep your engine ticking problem-free for years to come.
On the other hand, it’s a bad idea to drag your heels when you notice the oil pressure dropping. They can lead to reduced lubrication, cooling, and cleaning of your engine’s many moving parts. On top of that, some components require an ideal oil pressure to function, anyway. In all, motor oil pressure is an important reading to keep a close eye on, failure of which will no doubt cost you a whole lot more.
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