Engine flushing is a procedure that is used to clean the engine of sludge and other elements that build up in the lubrication system of mostly diesel and petrol engines. The main purpose of an engine flush is to clean and unblock the oil ways, prolonging the engine life.
Periodic flushing helps the components of the engine remain relatively clean and thus operate at optimum levels. But the biggest question is how often it should be done. When you look at many service cards for vehicles, they are flushed every service.
For a diesel engine, I would partly agree this is necessary, but for a petrol engine I would totally disagree. Flushing should only be done when an engine has been serviced routinely for a long time or when the oil drained is not as clean as the new oil put in the engine when it was last serviced, or when traces of sludge are seen when servicing. It is not right to flush an engine at every short interval service. Flushing oil is thin and can dissolve the sludge formed when old engine oil mixes with other elements which build up as engine oil is over worked.
After draining the engine without removing the oil filter flushing oil is then poured into the engine to the correct level, then the engine is started to allow the flushing oil to cleanse chemicals and to circulate throughout the lubrication system, following the same flow pattern as the engine oil that lubricates the engine components. As the flushing oil detergent cleans the oil passages and finds its way to the oil sump it comes along with the sludge and all deposits in the system.
NOTE: Do not run the engine for a long time without flushing oil since flushing oil is very thin. If it is run in an engine for a long time, due to pressure in the lubrication system, the flushing oil easily penetrates seals, which in turn can cause the vehicle to smoke. It should be run for a maximum of 3Â to 4 minutes, then be drained and new clean engine oil put together with new oil filters.
But even as engine flushing seems like a task that should be done from time to time, it remains a challenge to many mechanics and drivers determining when it should be done because. Not everyone agrees that flushing an engine is effective or that they should do it frequently.
While it is generally acknowledged that engine flush is very helpful in vehicles that do not move long journeys, especially home-to-office-and-back, which have not had an oil change as often as recommended because they do not move long enough to really warm the engine oil, some professional mechanics question the effectiveness of engine flushing. With vehicles that travel very long distances it is very hard to form sludge and deposits, as they generate enough heat that does not enable the engine to form sludge and deposits.
The build-up of sludge and deposits in old engines is very common due oil contamination. This sludge and deposits cannot be dissolved by the detergent chemicals in the flushing oil. This makes a bad situation worse. Instead of using flushing oil, it is recommended that the engine be dismantled and the components be thoroughly cleaned with paraffin.
It is advisable for a mechanic to first assess the condition of the engine oil before recommending flushing because in one way or another it may worsen the condition of the engine, making it start smoking, if the right procedures are not followed.