Your oil pressure gauge or warning light is there for a reason. It helps you infer how well lubricated your engine is. For the oil to move around the engine successfully, it has to build up the correct pressure.
If the pressure is too low, chances are oil isn’t traveling through all the channels and lubricating every component that needs that slick oil.
How Does Your Engine Build Oil Pressure?
Your oil pressure results from the oil pump forcing lubricant through channels in the engine block. The oil pump’s performance and the oil are the main determinants of your oil pressure.
Summary: The pressure pump compresses oil through the system building up pressure since it’s a closed system with resistance.
Pressure is the measure of force behind the oil and determines how far it can go even when traveling through restrictive joints, filters, and over tight spaces in precision milled engine components.
So, the pressure is a product of your engine oil’s viscosity and the power your pump can provide to pressurize the oil.
As such, it takes a few seconds for the oil pressure to build up to optimum after starting a cold car.
- Cold oil is heavier. It takes some extra force to pressurize it
- If your engine isn’t idling at the correct RPM on a cold start, the pump needs more time to build up pressure
What Causes Low Oil Pressure While at Idle
If your vehicle has an oil pressure gauge, you will get an accurate oil pressure reading every time your car is on. While the optimum pressure varies from engine to engine, the gauges have red zones on the low and high sides.
You should be worried whenever the gauge sits in the low or high-pressure red zones.
Most mainstream vehicles have an oil pressure light that illuminates when your oil pressure is too low. While you won’t know the pressure, it still gets the job done.
While constant low oil pressure is more common, low pressure when the engine is idling could point at a couple of issues that you must immediately correct.
The most common are:
Low Oil Pressure Levels
Since the lubrication system is a closed-loop, it also relies on a specific oil volume to build pressure to the optimum.
If the oil levels drop very low, the remaining space is occupied by air. Air compresses more quickly than oil, meaning the system can pressurize to the correct PSI with whatever air is available in the sump and engine block channels.
The oil pump will never attain the correct PSI no matter how hard it works.
After a low oil pressure warning, the first and simplest check your dipstick to check oil levels.
If you lost oil and the level is way below the minimum mark (or doesn’t register on the dipstick), then you have a culprit.
Don’t just top up the oil. You have to figure out why your engine is losing so much oil. You can use this guide to troubleshoot some of the common reasons why your oil levels are so low.
As you start driving, engine RPM picks up, and the oil pump can work harder to compensate; hence the low pressure warning will disappear.
Old and Dirty Oil
A neglected car with old and dirty oil will have a problem building up the correct oil pressure. The gunk and debris in the oil will clog channels, filters, and the pump.
If the gunk prevents oil pressure from accessing the sensor, your gauge will register less than ideal oil pressure.
When the gunk and impurities are too much, they make the oil heavier and harder to pump. This could take its viscosity beyond the pump’s capabilities, bogging it down.
The pump will either stop working or work at its peak, which will still not be good enough to generate optimum oil pressure.
If the gunk isn’t too nasty, increased engine RPM will send more power to the oil pump allowing it to push pressure high enough for the low pressure warning to go away.
ProTip: Always service your vehicle within the recommended mileage or time interval. Skipping or postponing an oil change will ruin your engine.
A Faulty Oil Pump
Even though oil pumps are not regular repair components, they get worn out and can fail, especially in high mileage vehicles.
You can also ruin your oil pump if you constantly run heavier than recommended oil or do not change your oil often.
An old or misused pump will be inefficient. It won’t generate enough pressure at idle because it will be spinning slower. This could remedy itself as the engine RPM picks up as you stop idling.
A failing oil pump should be replaced immediately. You don’t want it to shut down on you while out on the road completely.
A Problematic Oil Pressure Monitoring System
Sometimes, your engine’s lubricating system might be working fine, but the sensors monitoring it are acting up.
A faulty oil pressure sensor or a damaged processing circuit and display could lead you into believing you have low oil pressure while, in reality, you don’t
We did a post on faulty oil pressure sensors that addressed possible faults in the sensing system that could lead to false low oil pressure sensor readings.
A Worn-out Engine
Old engines that have been around for hundreds of thousands of miles eventually crack. Even the best motor will start spring tiny leaks, blockages, and component failures.
If you have an ancient engine that has never been rebuilt, seals, gaskets, and crucial components could fail and let oil leak. The pump could also be just too old to attain the correct pressure.
You Are Using the Wrong Oil
If you recently changed the oil and are noticing the problem, chances are you’re not using the right oil for your engine.
While getting oil viscosity is hard when dealing with multigrade oil, you can still be off the charts when using the wrong oil grade for your weather conditions.
An Overheating Engine
An overheating engine could also wreak havoc on your oil pressure readings. To begin with, heat affects oil viscosity, which affects how it responds to pressurization from the oil pump.
Additionally, an overheating engine could push seals and seams beyond tolerance leading to instantaneous leaks. Your oil levels could drop drastically enough, causing the oil pump, channels, filters, and sensor could fall out of spec as the temperatures pick up.
How to Get Rid of the Low Oil Pressure at Idle Problem
Now that we know what could cause low oil pressure as your engine idling, we can list out some of the things you can do to fix the problem.
If you are lucky, it could be a simple DIY fix. At times, you might need a professional or some time to eliminate different possible causes before implementing a thorough and possibly expensive fix.
Some of the possible fixes that work include:
Low Engine Oil
If your engine oil levels are low, the most logical solution would be topping it up. It’s normal for engines to burn some oil. However, they shouldn’t burn as much within service intervals.
You could refill the oil and monitor your engine to determine why it’s losing so much. Look:
- Oil puddles under the car
- Leaks around the oil sump or the drain valve
- Leaks around the valve cover gasket
- Blue smoke that hints at burning too much oil
Unmaintained Engine
Changing your filters and oil within the recommended interval will help you avoid problems caused by:
- Dirty oil
- Low oil levels
Consult your manual for directions. The standard interval for most noncommercial vehicles is 5000 miles or once a year, whichever comes first.
Other feasible solutions include:
- If you drive a high mileage car, have the oil pump checked and replaced if necessary
- Inspect and replace the oil pressure gauge and oil pressure sensor if necessary
- Ensure that you are using the right oil for your engine and climate
- If it is a very old engine, consider rebuilding it or using heavier oil to fill up larger worn out spaces better
What is the correct Oil Pressure When at Idle?
You don’t have to worry about the correct oil pressure in most modern daily drivers. After all, they don’t have an oil pressure gauge. They only illuminate a light when the ECU detects low or high oil pressure.
However, older vehicles, performance cars, and some mainstream trucks have an actual oil pressure gauge.
The gauge has red zones for low or high pressure and a normal pressure zone in between. This calibration is the easiest way to tell when pressure is too low. The gauge should never be in the red.
Consult your engine-specific manual to find out the correct upper and lower limit values for your engine.
Other Low Oil Pressure Signs and Symptoms
Apart from relying on the oil gauge to tell if you have low pressure, other symptoms could help you infer the same problem. It’s a great way to confirm that you have low pressure.
A Rattling Engine Noise
Low oil pressure means most engine components won’t get enough lubrication. You will start hearing more ticking, clunking, knocking, and grinding noises from your engine, especially when idle.
This will ruin your engine as the heightened friction will lead to faster tear and wear.
Dips in Engine Performance
Increased friction due to low oil pressure increases internal engine resistance. This will, in turn, reduce how much usable power you get from your engine.
Your Engine Runs Hot
Apart from just lubricating your engine, your oil plays a role in cooling your engine. If your engine oil is low, the engine might heat up even though your cooling system is working optimally.
Temperatures will either creep up above average as the cooling system works hard to compensate or downright overheat.
Check this too: Common Ford Ranger Questions, Problems & Their Fixes
What Damage Can Low Oil Pressure Cause?
The main side effect of low oil pressure is improper lubrication. This can wreak havoc on all the moving parts within your engine.
If left unattended, parts will shear off, jam, and grind themselves out of tolerance. Your engine will either seize up or become so worn out that it is inoperable.
Can I Drive With Low Oil Pressure
While your engine will still fire up and you can drive with low oil pressure, you shouldn’t hit the road.
You can cause irreparable or expensive damage to your engine. Troubleshooting the problem and fixing it is the most prudent solution.
Please don’t assume it is a false low pressure warning. The consequences of such an assumption can be dire.