Does your car seem to have oil pressure problems? High oil pressure is one of the most damaging things that can happen to your car. If this is your case, read on to learn what a high oil pressure condition is, identify the most common symptoms, locate the causes and how to fix everything back to normal.
Table of Contents
- 1 What Does High Oil Pressure Mean?
- 2 High Oil Pressure Symptoms
- 3 What Causes High Oil Pressure
- 4 Is High Oil Pressure Bad?
- 5 Can High Oil Pressure Damage An Engine?
- 6 How To Fix High Oil Pressure?
- 7 The Bottom
What Does High Oil Pressure Mean?
The lubrication system on a car is a highly complicated one, indeed. It allows metal parts, sometimes turning at over 20,000 rpm, to grind and rub on each other and to do so for hundreds of thousands of kilometers without overheating or needing to be replaced. This exploit is made possible thanks to your car’s lubrication system’s fine-tuning. Unfortunately, with time, components inside the system may suddenly fail and cause the pressure to rise uncontrollably.
Depending on the car you drive and how engineers designed it, the normal operating oil pressure may vary. In all cases, however, a high oil pressure condition happens whenever the pressure goes higher than expected.
On most vehicles, the oil pressure should stay between 40psi and 60psi. That threshold doesn’t include dry sump or high-pressure lubrication systems, though. Fortunately, these systems are usually reserved for high-performance and luxury vehicles only.
If you are lucky enough to have an oil pressure gauge in your vehicle’s dashboard, there should be some kind of lines or arrows indicating where the oil pressure should be. If it ever goes higher than the top line or reaches the red section of the gauge, you know for sure that your car is having a high oil pressure problem.
When in doubt, always make sure to look up the oil pressure specs in your car’s repair manual to find the correct operating pressure specifications.
High Oil Pressure Symptoms
The first sign that a high oil pressure problem is lurking in the shadows will be a blinking oil pressure warning light on the dashboard. As soon as the PCM notices that the pressure is out of threshold, no matter whether it’s too low or too high in fact, it will send a signal to light up the oil pressure light.
On newer car models, instead of a warning light, your dashboard may display something like “High oil pressure” or “oil system problem” in the information panel. In that case, you should stop the car as soon as you safely can. Driving with an incorrect oil pressure can quickly and extensively damage an engine, sometimes even to the point of no return.
Whining Sound Coming From The Engine
Whenever the oil pressure goes out of range, the added pressure will put stress to the engine components, resulting in a whining sound following the rpm of the engine. The same symptom can happen after the timing belt has been replaced and it’s been installed too tight. Any faulty bearing can also produce a noise sounding exactly like a high oil pressure condition. Keep this in mind when trying to locate a whining engine sound.
Trained ears like those of a certified mechanic should be able to easily differentiate both problems and make sure you aren’t looking for a problem that isn’t even there or replace perfectly healthy parts for no reason.
Lack Of Power
If the oil pressure gets really out of control, it could even stop the different components from moving or at least slow down their movement. The lubrication system and especially the section related to the lubrication of the crankshaft bearing, also called journal bearings, needs to be finely tuned to properly work. Even a slight drop or rise in pressure can greatly affect its efficiency and damage vital components.
Oil overflowing inside the combustion chambers can also prevent the spark plugs from igniting the fuel which will result in engine misfires and, ultimately, engine stalls. Once a spark plug is wet with oil, it won’t be able to spark anymore until it’s been thoroughly cleaned. If, when you step on the gas pedal, the engine dies out and you can see blue smoke coming out of the exhaust, your engine is burning oil. Oil consumption problems aren’t always related to a high oil pressure condition as it can also be caused by worn-out piston rings but if your engine is dying out when accelerating and blowing smoke, it’s strongly recommended to have it checked anyway.
A higher than normal oil pressure will also put stress on the numerous oil seals found inside a car engine. Oil seals are nothing more than thin pieces of plastic preventing oil from leaking out of lubricated components. Whenever the oil pressure reaches a high enough level, the oil seals will slowly start to leak and could even pop out completely.
When such a thing happens, you’ll notice small drops of oil where you normally park your car. If the leak is big enough, a strong burnt oil scent could be smelled near the underside of the car or inside the engine bay. If the oil is leaking on a hot component like the exhaust system or the engine block, blue smoke could start to come out the hood when the car is idling or behind it when you’re driving.
What Causes High Oil Pressure
Faulty Oil Pressure Sensor
The first thing to suspect whenever you see the oil pressure warning light come up is the sensor itself. It’s no use to start trying to investigate a problem without being sure that the sensor warning you there’s a problem is in good working condition in the first place.
Oil pressure sensors are usually located behind the engine, on the engine block itself or straight on the oil filter adaptor. Sensors installed directly on the engine are often near the exhaust manifold, meaning they’re constantly subject to high temperatures which tend to make them crack, letting water in and causing the internal components to either break or create a short-to-ground. Before a sensor stops working, it will often go awry and start sending an incorrect reading to the PCM, which could make the warning light come up for no reason.
Oil sensors are usually easy to get to and quite simple to test so make sure it works properly before going any further.
Incorrect Engine Oil Grade
Using a thicker oil grade than what’s recommended by your car manufacturer will also make the oil pressure go up. The principle is quite simple in fact. Thicker oil requires more power to move and won’t flow as fast in small oil passages, resulting in a higher than normal oil pressure.
There’s absolutely no good reason to use a thicker oil inside your engine. It was a common thing before 1980 or so, but newer vehicles simply can’t be driven with 20w50 oil to reduce oil consumption like they used to do. Recent cars rely on oil pressure for numerous reasons and especially those equipped with variable valve systems. On these vehicles, the oil pressure is used to set the valve timing correctly and using a thicker oil grade than what’s required will seriously affect the vehicle’s performance and fuel-efficiency.
Simply use the recommended oil grade and stick to it. Engineers know what’s best for your car.
Leaking Piston Rings
Piston rings are used to prevent air leaks between the combustion chambers and the oil pan as the pistons go up and compress the air/fuel mixture. In the case where one or multiple piston rings are leaking on your engine, compressed air will be able to enter the oil pan and can make the oil pressure rise dangerously. Such a condition is called a “blow-by” and it’s not a good thing at all.
The air pressure contained inside the combustion chambers is so high that, once it can enter the oil pan, it can cause seals and oil lines to blow out. Before it gets to that point though, you should notice an increase in oil consumption letting you know that your engine is burning oil. In some cases, you may also notice the oil dipstick being slightly pushed out of its tube when you open the hood because of the abnormal crankcase positive pressure.
Blow-bys can also be caused by worn piston ring seats or improper ring groove clearance. The only way to avoid excessive crankcase pressure is to ensure the engine is properly sealed. And this is also why blow-bys are especially common with forced induction engines as the pressure is considerably higher on this type of setup.
Faulty Oil Pump
Last but not least, if everything else seems to be in good working order, the last thing to suspect is the oil pump itself. This one comes last simply because it’s the less frequent one and also the most complicated component to inspect and replace.
Oil pumps are usually reliable and rarely come into problems. I’ve been a mechanic for the last 15 years now and I have still never encountered a faulty oil pump or needed to replace one. The explanation is quite simple truly. Oil pumps are nothing but rotors turning inside a housing, driven by a belt or a chain and that’s pretty much it. There are not that many components that can wear out and go bad. Not to mention that the internal components are constantly kept in oil, reducing the risk of rust build-up and such. However, the rotors could still potentially break and cause the oil pressure to go out of the normal operating threshold.
The worst thing with oil pumps is that since most of them are driven by the timing system and, therefore, are usually located behind all of the timing components. This means that to reach the oil pump to inspect it, you’ll need to remove the crankshaft pulley, the timing cover and everything it contains such as the timing belt/chain, pulleys, bearing and sometimes even the water pump.
Definitely not a job for the faint of heart.
Is High Oil Pressure Bad?
High oil pressure, just as low oil pressure, as a matter of fact, is obviously bad for your engine’s health. To correctly grasp how important a correct oil pressure is to your engine, just imagine the engine oil to be the blood in your body.
Is high blood pressure dangerous? Oh yes, it is!
Just as an abnormally high blood pressure level will put a strain on your heart and risk blowing out small blood vessel walls, a high engine oil pressure level will put a strain on fragile internal components and risk blowing out seals and lines.
Can High Oil Pressure Damage An Engine?
The lubrication system is so vital to your engine that without oil in, it probably wouldn’t even run for more than 30 minutes or so. All the metal parts moving would start to grind on each other, making the temperature of the engine to rise uncontrollably, ultimately leading to parts melting and seizing against each other.
A seized engine can only rarely be brought back to life without investing a hefty amount of money and even then, will often come into more collateral and expensive problems in the short term.
How To Fix High Oil Pressure?
Inspecting The Oil Pressure Sensor
The first thing to do when trying to fix a high engine oil pressure problem is to inspect and test the oil pressure sensor. Locate and remove the sensor and install a stand-alone oil pressure gauge in its place. Start the engine and let it run at idle until it’s warmed up. Once the engine has reached its normal operating temperature, read the value on the gauge and see if it’s within specs. If it’s not, you can test the oil pressure or replace it altogether. Pressure sensors are often inexpensive so you might as well just replace it. Just to make sure.
If the reading is the same on both gauges, the problem is located elsewhere.
Inspecting The Oil Grade
The next step will be to make sure that the engine oil in your engine is of the correct grade. The grade can change and fluctuate as engine oil degrades with time and can also vary depending on the outside temperature. The best way to make sure the oil in your engine is of the correct grade is simply to change it. Oil is also inexpensive when compared to the more expensive fixes coming down the line. If even after replacing your oil the problem is still present, you’ll need to take out your tools and put in some real work.
Inspecting The Piston Rings
Be warned that the following is not intended to be done by newbies. If you don’t know what you are doing, you could very well end up doing more harm than good here. If you aren’t sure about your ability to perform such tasks, I can assure you that you’ll be better off bringing your car to a mechanic right away.
Depending on the symptoms, you’ll need to take a different approach. For example, if you are having blow-by problems, the pistons will need to be removed to visually inspect the rings. To do so, you’ll need to disassemble the oil pan and the connecting rod caps to allow the pistons to be taken out. Depending on your vehicle, the piston will either need to be removed from the bottom or the top of the engine. To remove the pistons from the bottom, the whole front cover and crankshaft will need to be removed. To remove the pistons from the top, on the other hand, you’ll need to remove the engine head. Once you have the pistons in hand, inspect the rings and the ring seats and replace the faulty parts accordingly.
Inspecting The Oil Pump
If your car doesn’t seem to suffer from a crankcase pressure leakage problem, you’ll have to inspect the oil pump instead. Start by removing the timing cover and all of the timing components to be able to remove the oil pump. Once you have it in hand, inspect the relief valve and make sure it moves freely. Remove the pump body cover and visually inspect the drive and driven rotors for damage. Using a feeler gauge, measure the clearance between both rotors and make sure it’s according to specs.
In the unlikely event that the oil pump also seems to be in good working condition, the engine will need to be disassembled and the lubrication system will need to be overhauled completely. Something may be lodged into an oil passage, reducing the flow and making the oil pressure rise.
Lubrication systems are absolutely more complicated to troubleshoot than most other systems simply because of where the main components are located. That’s why being able to accurately pinpoint where the problem comes from based only on the symptoms can save you a lot of time and money. On the other hand, playing with the lubrication system without the proper knowledge and skill set can also end up doing more harm than good. If you aren’t sure if you are qualified enough to perform the more complicated tasks on this list, it never hurts to try to locate the source of the symptoms and collect as much information as you can about the problem. Being able to adequately describe what’s wrong with your car to your mechanic will also ensure your trip to the repair shop cost you as little as possible.