Oil pressure can be low for several reasons that do not require engine overhaul. These include the following:
Low oil level
Checking the oil level is necessary before deciding to repair the engine. When the oil level is low, it is difficult for the oil pump pickup tube to draw enough oil to maintain the correct pressure in the system. Low oil pressure under these conditions is a small evil compared to the damage that low oil pressure can cause. Probably the best preventive measure in this case would be to check the engine oil level at least once a week and add oil as needed.
Clogged oil filter
The simplest or most obvious cause of low oil pressure is a clogged oil filter. Unfortunately, there is no way to say for sure that this is usually the result of carelessness or error. If the oil has not been changed within the time that the engine suffered from low oil pressure, then the oil and filter should be changed.
Liquid or diluted oil
The idea of purchasing an oil that is too thin (i.e. low viscosity) is pretty stupid. If you are using oil that was purchased for the purpose of lubricating an automobile engine, it is almost impossible to purchase oil that will cause low oil pressure on its own. Some people may disagree with the statement that using a thick oil with a high viscosity will cause the oil pressure to rise. This is often true. However, if the oil pump and bearings are in good condition, even a low viscosity oil will be able to provide the correct oil pressure.
Another thing is diluted oil. The oil becomes diluted in several ways. Perhaps the most common way is described below. When the engine is running, especially after starting, some of the exhaust gas will blow past the piston rings and into the crankcase. These gases contain some unburned gasoline. Unburnt gasoline dilutes engine oil. This dissolved oil can cause low oil pressure. But an even more critical phenomenon can occur, which is that unburnt gasoline, combined with moisture in the crankcase, can form an acid that can damage bearings and their surfaces long before the low oil pressure caused by dilution damages the engine.
Another way: engine oil can become diluted due to fluid (coolant). If the cylinder head gasket begins to leak, or if the cylinder head or cylinder block cracks, coolant may leak into the combustion chamber and/or crankcase and dilute the engine oil.
Although low pressure due to dilution can be determined by a simple oil change, the question is: does the engine need major repairs due to a problem caused by diluted engine oil? Another question is: how much damage was the result of the dilution? A simple oil change can increase oil pressure, but the engine may already be damaged and must be repaired before catastrophic consequences occur.
Oil pump pressure relief valve stuck open
All engines are equipped with an oil pressure reducing valve in the oil pump. The purpose of the valve is to limit the oil pressure within limits that prevent the oil filter from turning into a frag grenade. Occasionally, the relief valve will stick open, allowing the oil to be pumped back into the oil pan by the oil pump. This fault is very difficult to identify and may require a complete engine overhaul.
If time is not a critical parameter, remove the oil pan and install a new oil pump. Although it is possible to repair the pressure relief valve, there is not much point in removing the oil pan and doing a "just in case" repair.
The oil that we pour into the engine wears out on its own even when the car is quietly in the garage - it oxidizes. Moreover, oil wear is inevitable during the active operation of the engine under serious loads. One of the big tests for an engine can be oil starvation - how to avoid it, the signs and consequences, and how to determine oil starvation, we will find out right now.
What is engine oil starvation?
Due to insufficient lubrication, aluminum almost melted
The lack of lubrication in some units in certain engine operating modes is theoretically called oil starvation.
For obvious reasons, in the absence of lubrication in rubbing nodes, they instantly fail. The danger of oil starvation motor is that it can occur instantly and almost completely destroy the main components of the engine:
- crankshaft,
- camshaft,
- gas distribution mechanism,
- cylinder-piston group,
- other vital and expensive components and assemblies.
Broken camshaft key (due to insufficient lubrication)
On level ground!
Oil starvation does not occur out of the blue , and as a rule, all the fault for a breakdown lies only with the owner of the car or the mechanics who made the repairs. As you know, the oil is in the crankcase in the amount necessary for lubrication and is supplied to the system using an oil pump. In the event that the oil cannot reach individual rubbing nodes, oil starvation occurs. There can be many reasons for this.
How to identify oil starvation
It was immediately obvious that the engine was "starved of oil"
First, about the definition of engine oil starvation, since the range of symptoms is quite wide - from a drop in engine power to overheating, extraneous noises and knocks. All this indicates the wear of certain components characteristic of each engine. For example, in the most common overhead gasoline engines, accelerated wear and increased noise during the operation of the gas distribution mechanism are often found.
Consequences
The consequences can be very different - jamming the camshaft, breaking the camshaft, bending the valves, destroying the rocker arms, turning the crankshaft liners, jamming the rings in the sleeve up to the destruction of the pistons.
In addition, oil scraper rings can lie down, which will lead to even greater oil consumption and engine seizure. Gray thick smoke from the exhaust pipe will just indicate a malfunction of the oil scraper rings and high oil consumption.
Causes of oil starvation
The operation of the engine in the oil starvation mode in almost all cases is accompanied by an increased temperature, which must be paid attention to. In addition, the oil pressure in the system may be either very low (as indicated by the oil pressure warning light on the instrument panel) or unstable. All this can be caused by such reasons:
- Insufficient oil level in the sump
. Lubrication is simply not enough to process all plain bearings, there is no oil film, the parts run almost dry. That is why at least once a week, and with active use even more often. In addition, it is necessary to carefully monitor oil leaks and, if necessary, take measures to eliminate leaks.
Oil dipstick in the engine (analogue above, original below). Incorrect dipstick readings may not indicate to the car owner about insufficient lubrication in time.
- Using the wrong viscosity oil . This is a very important point, since, for example, 5w-30 oil, when used in the summer, may not provide the required viscosity, engine lubrication will be insufficient, and pressure at high temperatures may drop critically. To avoid this, you must follow the recommendations of the car manufacturer in choosing engine oils.
- Clogged oil sump
. The oil pump is not able to overcome the resistance of a clogged mesh, so oil cannot be supplied in the right amount and under the right pressure to all nodes. The same applies to clogged oil lines. The ideal way out of this situation is to disassemble and mechanically clean the channels and the oil receiver, flushing agents can only make things worse.
Clogged oil sump
- Irregular or untimely oil and filter changes
. Each brand of oil has its own resource, which must be strictly observed. The lubricant loses most of its lubricating properties during operation and by the end of its service life can be almost completely oxidized and lose viscosity.
Oil filter disassembly
- Wear of oil scraper rings and increased oil consumption . Wear of valve stem seals, crankshaft oil seals will also lead to high oil consumption.
- Poor engine assembly after repair . A competent minder will never use sealant where a simple gasket is enough - the fact is that excess sealant is pressed not only out, but also inside the oil channels, clogging them over time.
- Failure, clogging of the pressure reducing valve of the lubrication system.
- Clogged oil filter.
Video about oil starvation of the engine at high speeds
conclusions
As you can see, there can be plenty of reasons for oil starvation, and in order to prevent a breakdown, you just need to check the oil level from time to time and follow the rules for replacing it, and eliminate leaks in time. Then the engine will last a long time and without expensive repairs. High-quality oil to all and good roads!
Oil filter, in English it sounds like an oil filter - it cleans the engine oil from impurities that get there during the circulation process. It can undoubtedly be called one of the key elements of the lubrication system of any internal combustion engine. The oil filter is located at the bottom of the engine.
Types of oil filters
At the moment, in the automotive industry are common:
- full-flow
- partially flow
- combined filters
Full flow filters have the simplest design and immediately pass through the filter block all the oil coming from the oil pump, which is then supplied to all engine lubrication points. The oil filter works on the basis of a bypass valve that regulates the pressure in the lubrication system. If the oil pressure of the oil exceeds the allowable value, it is reduced by the filter bypass valve. This is a certain disadvantage of this design, since when the filter is clogged, the oil flow slows down, the internal pressure rises, the bypass valve opens and passes contaminated oil into the system. The bypass valve, on the one hand, prevents immediate engine damage due to the termination of its lubrication, and on the other hand, it allows dirty oil to circulate, which is why the condition of the filter must be monitored very carefully.
Partial flow The engine oil filter cleans the oil longer than a full-flow one. In systems where it is used, the oil is purified gradually, circulating in two circuits at once: direct - from the pump to the friction zones, and cleaning - from the pump, through the filter and to the friction zones. In the process of circulation, oils from different circuits are mixed, which ensures the cleaning of the engine lubrication as a whole. Such systems are able to maintain the oil in good condition for a long period. Their significant advantage is that even with a clogged filter and broken valves, the oil flow will not stop and the engine will work.
Combined systems are created using technologies of both previous types. Here, the oil filter device guarantees the maximum quality of oil filtration and the longest period of its use.
Oil filter design
Almost every modern oil filter is not collapsible. However, quite a lot of cars (German, American) have a collapsible oil filter, which makes it possible to replace the filter element. The main advantage of such a filter is the ability to replace only the filter element, and not the entire assembly, which significantly reduces the cost of car maintenance.
Oil filter device.
Inside the body of the device is a filter element and a pair of valves. One of them is anti-drainage, designed to eliminate the reverse flow of oil. The other is a bypass valve that keeps the engine oil flowing even if the filter is clogged and the anti-drain valve is broken. The bypass clan also works when using oil with excessive viscosity, which is characterized by difficult filtration.
The bypass valve keeps the engine oil circulating even if the filter fails. The task of the anti-drainage valve is not to release oil from the filter when the engine is turned off, so that its circulation and lubrication of the motor begin simultaneously with its start.
The principle of operation of the oil filter
Common oil filter failures
Deterioration of engine performance, black exhaust when gassed, a drop or increase in oil pressure, the ignition of the corresponding lamp on the control panel - all these may be signs of a malfunctioning oil filter.
In addition to clogging the filter element, the problem may be related to the loss of elasticity of the anti-drain valve. This manifests itself in the periodic short-term inclusion of the controller on the dashboard, most often immediately after starting the engine. This is due to the fact that during parking with the engine turned off, oil flows out of the filter housing, and at startup it starts to work without proper lubrication.
Changing the oil filter is mandatory during an oil change. For this line, he manages to get very clogged.
Solving the problem is simple: you need replace oil filter or a filter element if it is a collapsible model. Suspecting the filter is not working properly, it is impossible to delay the elimination of the problem, because any deterioration in the quality of engine lubrication is its accelerated wear, which is fraught with much more serious malfunctions and major repairs.
Replacement frequency
No oil filter has an outstanding durability.
Exceeding the service life threatens to violate the intensity and quality of cleaning. The oil is not cleaned and remains dirty, which accelerates the wear of engine parts.
Related terms
Externally, the oil filter looks as simple as the task assigned to it. And this task is simpler than a steamed turnip: to clean it from dirt, which is a set of foreign inclusions that have entered the engine from the outside along with air and fuel, wear products of rubbing engine parts, as well as carbon deposits, coke and mucus-like oil decomposition products formed inside the engine.
Nothing else is required from the filter, so if you look into it through the threaded hole in the bottom, you can expect to see a paper filter element inside, which traps the dirt that has appeared in the oil. The better dirt is filtered out, the longer the motor will last, until eventually it becomes a victim of natural wear and tear.
However, if you disassemble the filter into separate components, it turns out that in addition to the filter element, there are some other details in it.
This is a bypass valve. It owes its appearance in the design of the filter to the fact that as dirt accumulates in the filter element, the resistance to oil flow through the oil filter increases. Because of this, situations are possible when the filter actually turns into a plug that prevents oil from flowing to rubbing parts. The bypass valve is just provided in order to prevent oil starvation in the bearings of the crankshaft and camshafts, the turbocharger cartridge, which are lubricated under high pressure, and their subsequent jamming.
As soon as the resistance of the filter to the oil flow becomes excessive, the valve opens, after which the oil flows past the filter element to the parts lubricated under pressure. However, another problem appears - the oil is supplied unrefined. Simply put, the lubrication system starts to work as if there is no filter in it at all, with all the ensuing consequences for the life of the engine. The question arises: when does the bypass valve actually open? This question was asked by our reader who sent a letter to the editors of the site, excerpts from which we present below:
“I came to the conclusion that in order to catch the moment when the bypass valve is activated, you can use a button with normally closed contacts and a control light. We connect one contact of the button to the filter housing, and bring the other out. When the valve is closed, it presses on the button. The contacts are open - the light does not light.
Prepared the filter. The button was soldered into a double-sided textolite. I drilled a hole into which I plugged a textolite insert with a button. It took some time to adjust the button height. While adjusting, the oil in the engine, according to the pointer on the dashboard, managed to warm up to 50 degrees. With such a warm-up, the control light signaled the operation of the bypass valve only at 6000 rpm and immediately went out. When the engine warmed up completely, the light did not light up at all.
The next morning I returned to the car. The alcohol thermometer on the wall in the garage showed 2 degrees below zero. I start the engine and the light doesn't even flicker. I add speed to 2500 - yes, it caught fire! I drop the RPM to 2000 and it goes out. So, everything works as it should! It remains to be seen how long the filter will last.
The first results appeared with a run of 1000 km. I attached a thermal sensor from a multimeter to the filter with electrical tape. Filter temperature - 4 degrees below zero. Exactly the same amount was on the thermometer in the garage. When I turn it on, the light comes on right away. This is understandable: the oil is thick in the cold, the filter is already a little clogged with dirt. He has no choice but to open the valve and let the dirty oil go directly. I'm waiting and watching the multimeter. The oil temperature has already reached 15 degrees Celsius, and the light bulb still does not go out!
Maybe the valve is stuck? I turn off the engine - the light goes out. I start - it caught fire. So everything works. Only at an oil temperature of plus 30 did the light go out at idle. At the same time, the temperature of the coolant has already risen to plus 55. I increase the speed to 2500 - the light comes on, slowly reset to 1300 - it goes out. Didn't wait any longer. But even so, there is already something to compare: it was the same on the new oil and filter, only then it was minus 2, and now the result is the same at plus 30. In any case, after a full warm-up in normal mode, the valve does not open, which means that the oil is filtered. What else is needed?
In the future, the situation only worsened. By a run of 2500 km at the start, the light comes on and does not go out at all. If, after a good warm-up, turn off, and the bypass valve naturally closes at the same time, and then start it, the light does not light up. I give speeds under 3000 - it lights up and no longer goes out. This means that the valve is not closed and allows crude oil to enter the engine lubrication system.
In addition to experiments on my personal car, I soldered the same buttons into the filters of my comrades' cars. That is, the operation of the bypass valve and how long the oil filter does its job has been tested on different machines, with different oils and different filters. The result is the same: 2500 km is the ceiling for the filter. Once, however, they reached 3000 km. Maybe the fact that the car made a couple of long-distance flights played a role.
I would also like to say a few words about the check valve. It is supposedly designed to prevent oil from leaking out of the filter when the engine is turned off. The idea is good, but only this valve holds the oil that is in the outer circuit, and for some reason the manufacturers do not take into account the fact that it can simply seep through the paper and drain through the inner tube! How long it will take for this to happen is hard to say, but it must flow out! The best option is when the filter is installed upside down, such a filter does not need a check valve at all. In other cases, only frequent windings or a clogged filter can help, when dirt does not allow the oil to seep through the paper. If not, we start our cars in the morning with empty filters."
Editorial
The recommended interval for replacing engine oil and an oil filter in Belarusian operating conditions is 12-15 thousand km for gasoline engines, and 8-10 thousand km for diesel engines. Judging by the results of the experiment set by our reader, only the first 2.5-3 thousand km after the replacement, the filter copes with its duties of cleaning the oil from dirt, and then it becomes less and less useful, if it remains at all.
Choose engine oil for your car at!
