Probably, as long as internal combustion engines have existed, there have been debates about whether it is necessary to flush the engine when changing the oil, or whether there is an urgent need for this. In general, the advisability of engine flushing is determined by a number of factors.
Motor oil is a universal liquid that performs two useful functions at once: lowering the engine temperature and lubricating its rubbing parts. By type, oil is divided into synthetic and semi-synthetic, and by viscosity it can be divided into groups W30 and W40. It also makes sense to take into account the manufacturer of the technical fluid so as not to fall for a fake.
With prolonged use, the oil loses its beneficial properties, which leads to overheating of the engine and rapid wear of its rubbing parts. Therefore, the engine oil should be changed on time, or even earlier than scheduled. But depending on what kind of fluid will be replaced, the engine may also need additional flushing.
In what cases should you not flush the engine when changing the oil?
Flushing the engine when changing the oil is not a mandatory procedure, and sometimes it does more harm than good.
Untimely flushing of the internal combustion engine costs the driver not only money, but also time if the procedure is carried out independently. But such manipulation does not affect the quality of work in any way. To improve engine lubrication, it is enough to change the oil ahead of schedule.
But you can ignore it only under the following circumstances:
- The car was purchased new, operated by one owner, mileage less than 50 thousand km;
- The car was purchased from an owner whom you know; you are sure that the previous owner changed the engine oil on time;
- The power unit has been inspected; there is no dirt or thick deposits under the valve cover with a consistency similar to graphite grease; when the engine starts, the low oil pressure light quickly goes out.
- This is not the first time the technical fluid has been replaced, and you know exactly what is currently in the engine (the same applies to cars purchased at a dealership - they are accompanied by a technical certificate where you can see the type and manufacturer of the oil).
- The replacement is made with a technical fluid of the same type, or with a higher quality analogue (high-quality oil has a higher viscosity, due to which it is not afraid of the sediment left by previous technical fluids of poorer quality. The only exception is replacing mineral water with synthetics. With such a difference in quality, flush the engine required).
Video “Cleaning an engine with serious contamination”
As you can see, flushing the power unit before changing the oil may be necessary. Before choosing one method or another, it is recommended to take the advice of a professional. Be sure to watch the video before starting work (the author of the video is Denis Gorban).
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When is it necessary to flush the engine when changing the oil?
Most high-quality motor oils, when circulating through the system, leave a thin protective layer on the rubbing surfaces of the engine. But washing reduces this protection to zero. Therefore, it should be done only as a last resort. For example:
- The car has a mileage of more than 250 thousand km;
- Bought second hand and there is no confidence in the high-quality service of the power unit by the previous owner (especially true if it is a traveling car from a company, a taxi, or has changed many owners);
- The inspection revealed a large amount of dirt deposits inside the engine; the warning light does not go out for a long time or does not go out at all after starting the engine;
- The motor is overheating and the water cooling system is working properly.
If the car was purchased secondhand (the condition of the oil in a used car always raises a lot of doubts, which is why its replacement should be carried out only with preliminary washing.
Moreover, it is advisable to replace technical fluids on a used car immediately after purchase, since there is no guarantee that it has not already become unusable. And receipts provided by the seller for timely maintenance do not provide guarantees to the buyer, since such documents can easily be forged);
If antifreeze gets into the engine oil (a similar phenomenon occurs when low-quality gaskets are installed on the internal combustion engine. In order to completely wash the antifreeze out of the system, it is advisable to flush it at least 2 times).
If the new oil has a distinct quality and viscosity (when replacing synthetics/semi-synthetics with mineral water, or vice versa, when replacing mineral oil with synthetic oil.
If the quality of technical fluid is improved from mineral water to semi-synthetic, then flushing is not necessary. The same applies to changing oil from W30 to W40. Such a replacement will not require flushing. But when switching from W40 to W30, you will have to clean the engine).
It is also advisable to flush the internal combustion engine if the engine using old oil is overheated. Otherwise, there is a risk of contamination of the block with metal shavings.
What to look for when choosing
To choose the right engine flushing oil, you must follow at least two instructions:
- by area and method of application of a specific composition (indicated on the container);
- car manufacturer's recommendations (sometimes flushing may be limited or contraindicated).
The choice of high-quality flushing oil today is not particularly difficult. Domestic options confidently maintain the quality bar, and the results obtained from their use are quite satisfactory to car owners.
Flushing additives
If you need the greatest effect, it is recommended to use expensive washes from well-known brands. Such a choice will be completely justified. For some reason, in the world of automotive lubricants, it is not customary to counterfeit flushing compounds even from well-known and expensive manufacturers.
It is difficult to say which flushing oil is better. All compositions will have some effect. But it is impossible to reliably assess this effect due to the large number of variables (degree of engine contamination, chemical composition of pollutants, engine characteristics, etc.)
Assessing the need for engine flushing when changing oil
To assess engine contamination, it is not at all necessary to completely disassemble it; just lift the valve cover or at least shine a flashlight into the oil filler neck and see if there are deposits.
When buying a used car, hardly anyone will allow you to remove the valve cover, so you should consider what is under the oil filler neck. Sellers who are dishonest can wipe the elements of a dirty motor under it to give it a shine.
It should be borne in mind that when changing the oil, with or without flushing, a certain amount of old oil always remains in the engine. This is especially true if the replacement is carried out in a car service using the suction method, and not through the drain hole at the bottom of the engine crankcase.
Even a 1.6-liter engine may have 300-1000 grams of old oil remaining. You can approximately estimate the amount of residue by comparing the volumes of new oil poured and the required value in the manufacturer’s specifications.
What is observed after draining the lubricant
When the lubricant is replaced, the used oil is drained. To activate the process, it is recommended to warm up the engine to 75...80 ⁰С. As a result, the viscosity decreases. Residues flow out of the channels through which the fluid is supplied to the friction zones.
In fact, complete removal does not occur. Repairers claim that when disassembling an internal combustion engine, they gain up to 300...500 ml. Especially a lot is observed when removing the cylinder head, as well as when disassembling the crank mechanism. These nodes have many channels.
Sometimes they are clogged with small metal particles, as well as soap formed when the oil comes into contact with the coolant.
Quite often, emergency repairs are due to the fact that the obstacles to the movement of fluid were not eliminated in a timely manner. When rinsing, the resulting soap particles dissolve and are washed away. Solid particles are also removed from the supply channels of the rubbing elements.
Does flushing the internal combustion engine depend on the type and type of oil being poured?
There is an opinion that it is necessary to flush the engine when changing the oil if, for example, oil from another manufacturer is filled, semi-synthetic or mineral oil is replaced with synthetics. In any case, washing is not worth doing.
This process is carried out only to clean the engine of internal deposits. Any cleaning products have a fairly aggressive detergent composition. After incomplete draining, they mix with new oil and can harm the engine.
Also, some drivers believe that it is worth doing a flush when changing oil manufacturer. This is wrong. There is no guarantee that when buying oil from the same manufacturer, you will receive a product with the same composition.
Firstly, the manufacturer himself can change the recipe, and secondly, there is always a risk of buying a fake. The base oils mix well with each other. The differences are in the additives, but their mass is small and they do not have a significant effect when mixed.
When replacing, you should pay attention to the condition of the drained oil. If there are a lot of thick inclusions or lumps, then it is better to flush the engine when changing the oil, or next time replace it after 3-5 thousand km along with the oil filter.
Repeated replacement with a shorter mileage interval is preferable. Flushing compounds can quickly wash away all deposits, but their circulation through the lubrication system can cause harm to the internal combustion engine system.
Types of flushing oils
There are fast-acting and long-lasting oils. Drivers often choose the fast-acting option. Firstly, products of this type are represented quite widely. Secondly, this procedure takes only 15 minutes. But the engine should only run at idle speed. You can’t accelerate, much less drive, on such oil. Yes, and keeping it longer than prescribed is also not recommended. But with another type of flushing oils you can drive several tens of kilometers. Moreover, it is even useful. But the requirements for engine operation are quite stringent. For example, you will have to drive only at the lowest speeds. No trailers, much less towing. You can't brake the engine either. Gradually, such oils are disappearing from store windows, because drivers are increasingly choosing a quick wash. The oil must fulfill its main function - to dissolve dirt and deposits. But the negative impact on gaskets and other seals should also be taken into account.
Types of flushes
The procedure for cleaning the engine when changing the oil directly depends on the type of flushing fluid used:
Special flushing oil
This is a technical fluid with a mineral composition, which includes many active additives. Unlike the “five-minute”, it does not wash off the protective layer from the rubbing parts, having a milder effect on the internal combustion engine. But you also need to use it no longer than 5-10 minutes, at idle speed
Manufacturers recommend using it before adding new oil. You need to drive the flushing oil in a gentle mode (as during break-in - low load, speed no higher than 3000 per minute) for 100-200 km, and then fill in new oil and change the filter.
Regular motor oil
A technical fluid with reduced quality or viscosity is used. You can flush the engine with the same oil that is planned to replace the previous fluid. To do this, the engine must be operated for 1-2 days and the lubricant must be replaced again.
Chemical compositions of the “five-minute”
These are organic solvents that resemble ordinary water in consistency. To clean the engine, such liquid must be poured into the engine, instead of old oil, and let it run for 5-10 minutes in idle mode. Then the oil is changed to a new one, with the oil filter replaced.
It is strictly forbidden to operate the engine for five minutes, as there is a chance of heating the rubbing surfaces, followed by a wedge of the piston group.
The compositions have an aggressive composition; when mixed with old oil, unwanted chemical reactions can occur. The problem is aggravated by incomplete removal of the composition when adding new oil.
Well-known manufacturers of internal combustion engine cleaning products
"ZIK"
The products dissolve formations and contaminants in a car engine. In addition, they protect parts from corrosive and oxidative effects and prevent lubricant foaming. Liquids do not harm seals and extend the service life of the engine.
"Rosneft"
Rosneft products are mineral water produced by combining various additives. They are used for quick and high-quality cleaning of engines running on gasoline/diesel. Rosneft liquids can effectively remove carbon deposits and other deposits.
"Spectrol"
The company's products are used in gasoline/diesel engines. They make it possible to get rid of various formations that appear in the internal combustion engine after prolonged use.
The main purpose of Spectrol fluids is to remove the sediment remaining after draining the used consumables and negatively affecting the performance of the engine.
"Liqui Moly"
Currently, the funds of this organization are most popular among Russian consumers. The Internet is filled with reviews about their use, and on websites drivers actively discuss the effectiveness of using these fluids.
Liquid Moly products clean the engine of carbon deposits that have appeared, which shorten the operating period of the power unit. This is very important for cars operated in fairly harsh conditions, for example, in large cities.
"TNK"
TNK products are intended for flushing the lubricant complex of Russian cars before changing the oil. They are made from mineral water to which detergent additives have been added.
The manufacturer claims that its products clean the internal combustion engine from carbon deposits. It is worth mentioning that TNK flushing fluids include anti-foaming additives that allow high-quality cleaning of the power unit in any conditions.
Died
I love cars in all forms.
I've been tinkering under the hood since childhood. I know all the ins and outs of Russian cars and some imported ones. I will be happy to share my knowledge with everyone who likes to do everything with their own hands. May be interesting: Changing engine oil yourself in a Mitsubishi
