Fluctuating oil pressure
When the RPM reaches 2800 and over, the oil pressure gauge starts fluctuating erratically. The engine works fine and the gauge shows normal pressure at RPMs lower than these. What might be causing this?
Experienced mechanics share their insights in answering this question :
The fluctuating oil pressure indicates an inadequate oil supply to the oil pump. It is possible that there may be some trash or sludge buildup on the pickup tube screen limiting the oil supply at the oil pump. An engine flush with a flushing agent may correct the issue with the next oil change. If this does not correct the issue, the pan will need to be dropped and the pickup tube and screen inspected. Also the clearances in the pump should be checked. You may want to enlist the help of a mechanic, such as one from YourMechanic, who will be able to accurately diagnose this fluctuating oil pressure issue.
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This is normal operation for your oil pressure. The faster the motor spins, (RPM, revolutions per minute) the faster the oil pump spins creating higher oil pressure. Keep in mind, most gauges aren`t accurate. The only way to get an accurate reading is with a quality oil pressure tester.
Hi There, This is completely normal for the oil pressure to increase when accelerating. The oil pressure inside the motor increases as the motor works harder. Your oil pressure switch reads this change in pressure and relays this to the oil pressure gauge.
Dirty or contaminated oil filter: The oil filter is there to filter out impurities from the engine oil. Over time, particles from dust, soot, rust, and gum get deposited in the filter and begin clogging the system. This leads to more resistance and higher oil pressure.
What it means is the bypass valve in the oil pump doesn`t bleed off pressure until it reaches “beyond” 80 psi. Starting up a newer cold engine, that is probably normal. Eighty psi is pretty high for an engine that is at operating temperature.
That`s what happens when you put too much oil in your car. Foam will not supply oil pressure, so the gauge reading will be erratic. You have to drain out the excess oil and hopefully that problem will be fixed.
Higher engine speeds result in higher pump output pressure while at lower engine speeds pump output pressure will be lower. Minimum engine oil pressure, at idle, varies by engine but you should see about 10 PSI. Pressure could rise to 40 to 60 PSI at high engine speed.
This is completely normal. With oil at full operating temperature of 200+ F., your oil pressure will vary depending on engine RPM. Just as an example my 5.3 Chevy engine using the recommended 5–30w oil will show about 45 psi at 2100 RPM (65 mph) but drop to roughly 35 psi at idle when the oil is fully hot.
The most common cause of high oil pressure is engine temperature, which is ultimately what dictates the temperature that the oil reaches. Malfunctioning engine components can also cause oil pressure to rise.
10 psi per thousand engine rpms is a good general rule of thumb for acceptable oil pressure.
Suppose you put a thicker oil in a modern engine. One of the things that`s going to do is increase oil pressure. Variable valve timing works off oil pressure so you might wind up with a check engine light and a code for the variable valve timing, which could lead to some expensive repairs.
Overfilling also increases oil pressure, putting more stress on seals and gaskets that keep oil from leaking out of the engine or going places it shouldn`t on the inside. Over time, the added stress accelerates wear on those seals and gaskets.
High oil pressure is usually caused by dirty oil filters and debris. Oil carries dirt particles like soot, dust, and sludge with it. These particles build up over time. Other signs of high oil pressure (that aren`t the “check oil light”) include engine sputtering, oil leakage, and a burnt oil smell.
Normal engine oil pressure is between 25 and 65 PSI. While the ideal oil pressure can change depending on the make and model of your car, the general rule is that oil pressure should be above 25 and below 65 PSI (pounds per square inch).
Low oil level is the most common cause of low pressure; it`s also the easiest to fix. Oil changes are important, and between oil changes, it`s equally important to regularly check your motor oil level and top it off as necessary.
The basic rule is 10 psi of oil pressure per 1,000 rpm at normal operating temperature. For example, if you`re highway cruising at 2,500 rpm, you should have 25 psi. At idle, the same engine might have 10 psi or less.
The reason that driving fast burns oil at high RPMs is because you`re putting extra pressure on seals and gaskets in your car. Even new seals and gaskets may experience a bit of seepage that eventually is consumed in the combustion chamber of the engine.
Most carmakers suggest that oil pressure should be around 30 PSI when running idle and about 60 PSI when the engine is running at higher speeds. If you check that the oil pressure is lower than 20 PSI. If you notice that the oil pressure is low than 20 PSI, you should check as soon as possible.
Low viscosity generates less resistance to flow through the system, which is translated as lower pressure by the pressure gauge or sensor. Viscosity that is too high may produce greater resistance from the oil being pumped, leading to a lack of lubrication in the system and consequently lower pressure.
Yes, around 40 lbs is norm, but but if she holds at 30 lbs. and rises when rpms are brought up, it is ok. May want to consider putting in a high volume oil pump if there are a lot of miles on the engine.
It`s best to use the oil viscosity recommended in the owner`s manual, but using a slightly thinner or thicker oil (lighter or heavier viscosity) generally poses no long-term harm.
If you use your vehicle in urban conditions, often sit in traffic jams, drive at high speeds, and your car is old, buy oil with the 5w40 viscosity. But if you prefer calm driving, and fuel economy and eco-friendliness are important for you – choose a product with 5w30 marking.
5w30 motor oil is less viscous (less thick) at very low temperatures compared to, say, 10w40. It has a hot viscosity grade of 30, which means it is less viscous at high temperatures than an oil such as 20w50.
Colder temperatures can actually increase oil pressure, but the churning oil in the engine may create air bubbles. Thicker oil may hold onto those air bubbles longer, making the oil pressure gauge read a lower value.
Relevant Questions and Answers :
the most relevant questions and answers related to your specific issue
lost all oil pressure, replaced the oil pump, low oil sensor, oil pressure sensor, oil pan gasket,
ANSWER : The fuel pump will not stay on if you loose oil pressure. This is why it is shutting off. The loss of oil pressure may be from bad crankshaft bearings or camshaft bearings. The engine oil pan should be removed and the oil pump needs to be checked to ensure that you put in the pick up tube seal to the pump and connected the pump to the block. Then remove at least one main bearing cap and inspect the bearings for excessive wear and crankshaft damage. If you need some help with this, consider YourMechanic, as a certified technician can help diagnose the issue with your oil pressure firsthand and help you fix it accordingly.
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My car has low oil pressure. I’ve already changed the oil pressure sensor 3 times.
ANSWER : If you have replaced the sensor three times and it did not fix the problem, then you may have problems with the oil pressure being low at idle due to wear in the engine bearings. The reason it would be fine sometimes and not others may be due to engine load and temperature changes. Have the oil pressure tested at the sensor port to see if it is low and needs engine repairs.
I recommend having a certified mechanic, such as one from YourMechanic, come to your location to perform an inspection to determine why the Oil Pressure Light is on.
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Low oil pressure light comes on when idle. Check engine light is on as well. Both came on after getting an oil change 3 days ago.
ANSWER : It is possible that they put in the wrong viscosity oil. In rare instances, a defective filter will also cause low pressure. If there is too much oil, it will aerate and cause low pressure. Be sure the oil level is really not above "max". The P2187 code will appear if the oil fill cap is not tight but it will also appear due to a myriad of causes because that code only "generally" identifies a lean running condition. Consequently, numerous parts would have to be tested including the O2 sensor, gas cap seal, manifold air leaks, any vacuum leak anywhere including PCV and EVAP systems, exhaust leaks, and fuel system faults such as failing fuel pump, clogged filter and more. Since the car has relatively low mileage, you would not expect a failed oil pump, although the pressure sensor (or switch) could be bad. However, the occurrence of the oil pressure warning light is quite coincidental to the oil change, thus I would suggest bringing the car back and asking them to redo with a new filter and double check the viscosity of the new oil that they use. If the problem persists after that, you will have to test actual operating oil pressure (at idle for instance) as well as the oil pressure switch. Finally, if the oil pressure warning light comes on continuously, unless the warning circuit itself is malfunctioning, that means the oil pressure is too low to operate the engine without damaging it. Anytime the light comes on for more than literally an instant, you should shut down the car and thus an issue like this obviously has to be repaired.
If you’d like, a YourMechanic certified mechanic can come to your home or place of business to inspect the vehicle and perform an oil pressure light is on inspection to diagnose the vehicle and suggest potential repairs.
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Truck has oil in it but when i am idling at a stoplight, the oil pressure gauge drops and says low oil 2003 Dodge Ram 1500 4.7L
ANSWER : Hello – assuming an adequate oil level, which you have checked, there may be a real oil pressure problem. It’s worth checking with a know working oil pressure gauge, so that you can get the real readings (i.e. 40 psi at running RPM, 10 psi at idle – both hot – would be acceptable). It’s expected that your oil pressure will drop at a hot idle, as long as you have good pressure above idle. Low hot pressures all around are indications of excessive connecting rod or crankshaft main bearings, camshaft bearings, or oil flow bleeding off elsewhere in the engine. For professional assistance, I recommend a low oil pressure inspection performed by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, and give you an accurate assessment of damage and cost estimate for repairs.
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Are there accurate electrical oil pressure gauges that will beep me when my oil pressure goes too low and how do they work?
ANSWER : Oil pressure reporting systems with programmable audible alarms are readily available. An example is the CruzPro Digital Gauge but there are many other vendors and you really have to do a product comparison and look at all the reviews. Once you select an audible alarm based system, if you desire a professional installation, you can use YourMechanic’s oil pressure sending unit service page to request installation. Of note, most damage to engines related to oil starvation occurs in the few seconds after starting. Therefore, I would recommend you FIRST install a pre-pressurization system as that will give you the most bang for the buck and indeed solve what is an immediate problem in all engines. An example of this product is the Insta-Lube Engine Pre-Lube Kit. Again, though, there are many variations on this solution. I highly recommend pre-lube and the only reason all engines do not have it is such a system adds cost and complexity to motor vehicles but it solves a real problem. A certified mechanic from YourMechanic can install such a pre-lube kit as well, if you desire. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.
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replace oil pump and pick up tube
ANSWER : Hi there. Typically when the oil pressure changes based on the type of oil you are using, it’s an issue with the pick-up itself. Quite often, the wrong sized or style of oil pump or a pick-up line that is too short / long, can cause inconsistent oil pressure. It’s also possible as you indicated that the oil pickup screen is clogged with sludge or debris (especially if the engine has not been rebuilt). It might be a good idea to have a professional mobile mechanic complete an oil pressure light inspection to help you pinpoint the source of the issue and recommend the right repairs.
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Does my vehicle have an oil pressure sender or oil pressure sensor or both and where is it located?
ANSWER : Your motor (454/7.4L Big Block Chevy) should have an oil pressure sending unit that is typically mounted just above the oil filter housing. This is a relatively small unit (about the diameter or a quarter or slightly bigger) with threads going into the engine block and a line coming out of the other side of the unit. Your oil pressure fluctuation sounds like this may be a case of a failing sending unit. If you are not able to replace this on your own, feel free to schedule an appointment with one of our expert mechanics here at YourMechanic to come to your location to replace your oil pressure sending unit.
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Chevy 5.3l – Lost oil pressure, why?
ANSWER : Hello – since you didn’t appear to be leaking oil in a significant way (busted oil line, hole in the pan), I suspect that the oil pressure relief valve may have been stuck in the "relief" position. Some of the early 5.3l engines had trouble with this – galling in the pressure relief valve bore. Pull the plug, spring and ball out to be sure the spring hasn’t broken. Light tapping on the block may be required to release the stuck valve. Good luck!
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