Description:
7 min
Engine Flush
A characteristic of any internal combustion engine is the accumulation of sludge and deposits. Contamination can lead to engine failure, making flushing necessary.
Changing the engine oil is a routine procedure that drivers typically perform at a service station every 4,000 to 9,000 miles (7,000 to 15,000 kilometers). The specific interval depends on factors such as the quality of the oil, the age of the car, the type of fuel used, and other operational characteristics.
During an oil change, the question arises about the need for an engine flush. Engine flushing is designed to remove contamination residues from the engine lubrication system that remain during regular oil drainage.
An engine flush is a preventative procedure that cleans the internal combustion engine by removing deposits, sludge, and other contaminants. Special additives or oils are used for this purpose. They help break down products of incomplete fuel combustion, wear from frictional components, and other solid deposits within the system.
Despite the variety of available options, whether it be quick flushes or longer procedures, these "cocktails" work similarly. The flush solution is poured into the oil inlet, and the engine is left to idle. During this time, the liquid circulates throughout the system, flushing out contaminants.
This procedure offers several advantages:
- Reduces wear on engine surfaces by stabilizing the oil film.
- Extends the lifespan of new oil and the oil filter.
- Dissolves engine deposits.
If the oil passages become clogged, the engine may struggle to perform at its full capacity. Flushing helps prevent blockages and subsequent problems.
Clean oil remains effective for a longer period. This is particularly true when oil changes are performed at extended intervals. Flushing helps avoid mixing remnants of old oil with the new one.
The accumulation of deposits and particles directly affects the operation of internal combustion engine parts. The flushing procedure restores the oil film on the rubbing surfaces.
A clean system allows new oil to circulate freely, leading to improved engine performance.
When is an engine flush necessary?
- Modern engine oils have cleaning additives, but their effectiveness diminishes over time. Alongside high mileage, irregular oil changes, or the use of questionable lubricants, contamination increases. Flushing helps eliminate them.
- Neglecting oil changes on time is a primary cause of deposits and sludge. Even if all deadlines are met, the system cannot be completely cleaned, and a balance of 8% to 20% of contamination may remain.
- If you've purchased a used car, it's impossible to know the frequency and type of oil used by the previous owner.
- When switching from one oil base to another, such as from mineral to synthetic. The same applies when gradually adding different oils to the engine, even if they appear similar. Each mixture has a different composition, and it is best not to mix them.
- After prolonged vehicle inactivity or extended periods of driving under challenging conditions.
- Engine flushing may be advised if antifreeze or low-quality fuel enters the system.
During engine operation, the oil inevitably oxidizes due to thermal and mechanical loads, as well as the presence of foreign substances. Oxidation results in solid products appearing in the oil, which can deposit on engine parts, clogging gaps and oil passages.
Failure to change the oil in a timely manner can lead to the production of acids that corrode engine elements and alter the oil composition through the consumption of alkaline additives. It can also lead to the accumulation of resins, carbon deposits, sludge, soot, and varnish.
If contaminants are not removed promptly, engine oil starvation can occur, leading to increased fuel consumption and severe damage to the internal combustion engine. This is when flushing becomes necessary.
It's important to note that engine flushing is not required with every oil change.
When you don't need an engine flush?
Sometimes, accumulated deposits in the system act as a protective barrier for worn or cracked seals, preventing oil leaks. In such cases, it is better to follow an expert's advice and reduce the oil change interval while using a high-detergent lubricant. Additionally, engine flushing is not necessary:
- When purchasing a new car, or if the manufacturer explicitly prohibits it. For example, General Motors stated in one of its official bulletins that it does not approve or recommend flushing its gasoline engines from the 2020 model year due to potential component damage. Similar instructions can be found from other manufacturers.
- If you are the sole owner of a car and have consistently changed the oil on time, flushing the engine is not necessary.
- In cases of severe engine contamination, as there is a risk of damage.
Types of engine flushes:
There are several types of engine flushes, differing in the active substance and the procedure:
1. "Five-Minute" flush: Sold in small bottles, these contain aggressive chemicals for instant effects. Solvents and various additives are included. Flushing with a "five-minute" product is performed at idle without draining the main oil. After use, it is removed, the filter is changed, and fresh oil is added.
2. Flushing oil: This method utilizes mineral oils with numerous detergents and neutralizing additives. These compounds are sold in canisters of 5 or 6 liters, sufficient for the entire system. They completely replace the old oil, and the engine runs at idle. Afterwards, the flushing oil is drained and replaced with the regular lubricating fluid.
3. Long flush: These liquids have a similar composition to "five-minute" flushes but require a longer duration of use, typically around 60 miles (100 kilometers). It is advisable to avoid extreme conditions during this period. After the mileage is reached, the flushing liquid, along with the dissolved contaminants, is drained, and new oil is added.
4. Oil flush: In this method, the same type of oil that will be used afterward is introduced. The car owner changes the oil to a new one and drives 600-1200 miles (1000-2000 kilometers) before performing another oil change. This method is considered one of the safest, although it has a slightly less potent washing effect compared to other options.
Modern flushes are effective due to their increased concentration of active chemicals, which dissolve deposits rapidly. They also contain additives that protect seals and gaskets from damage by forming a protective film.
Choosing an engine flush:
The most effective option in terms of efficiency is the "five-minute" flush. However, it is possible to use products that are added several hundred kilometers before an oil change or immediately prior. When selecting a flush, consider the following factors:
- Engine type: Choose a product suitable for the specific engine type, such as gasoline or diesel, considering additional features like turbocharging or forced induction. Separate lines of flushes are available for motorcycles, trucks, and marine vehicles.
- Aggressiveness of the composition: If unsure about the necessity of a strong flush, opt for milder formulations. This is especially important for engines with high mileage and a history of operation in challenging conditions. Some formulations may indicate that flushing is safe for rubber seals.
- Manufacturer: It is advisable to purchase flushing products from trusted brands and reputable stores to avoid the risk of counterfeit products.
Is it possible to eliminate the need for engine flushing?
It is worth mentioning that the use of special cleaning products for the engine is more common in Europe. Manufacturers in these regions include certain types of oils and other products in their lines due to market demand. In countries like the United States and other developed nations, the demand for such products is lower
. In these regions, the prevailing opinion is that these products are a waste of money, and oil manufacturers often assert that their oils do not require flushing. Shell has taken a similar approach. Their modern oil lines, such as Shell Helix Ultra:
- Help remove deposits that result from using less effective lubricants.
- Provide exceptional engine protection and cleaning properties, even when adhering to longer drain intervals recommended by equipment manufacturers.
In conclusion:
It is recommended to change the oil at least every 7.5 thousand kilometers (4,700 miles), which is twice as often as suggested by most automakers. By following this guideline, regardless of operating conditions (city or rural), you can avoid accelerated wear of engine parts. For new car owners, it is crucial to adhere to this rule immediately, while second-hand car owners should first perform flushing operations as described above and then follow the same recommendations.
It is advisable to refrain from attempting to flush the engine "just in case." Use cleaning fluids only when there are objective reasons, such as the presence of deposits in the oil. Another important point is to choose high-quality cleaning compounds and follow the instructions for their use in each specific case. Failure to do so may result in engine damage, leading to expensive and lengthy repairs. Ultimately, the best approach is to prevent the need for engine flushing rather than relying on the complexities of the process and spending money on visits to car service centers and the purchase of special compounds.