In engine maintenance/servicing, an oil change is often seen as the solution for a variety of complaints: rough running, increased wear, or contamination. In practice, however, new engine oil often doesn’t have the desired effect.
The cause? Residual contamination in the lubrication system.
Without prior cleaning/flushing, a large amount of old oil, sludge, and deposits remain in the engine. New oil mixes with this immediately, largely negating the benefit of changing the oil.
What is left behind after a standard oil change?
When draining engine oil, only a portion of the contamination is removed. In practice, the following remains:
increased deposits of tar, varnish, carbon particles, and sludge in the lubrication system and piston grooves.
This contamination is often invisible, but it does directly affect lubrication and engine performance.
New oil mixes with old contamination
When new oil is added to a contaminated system:
- it mixes immediately with the remaining old oil
- it absorbs the left over contamination and sludge
- it loses its lubrication and cleaning effects faster
The result is that the new oil becomes contaminated more quickly, degrades more quickly and cannot optimally perform its protective function.
Limited effect on wear and performance:
When contamination remains in the lubrication system, the following can occur:
- reduced oil flow
- higher internal friction
- increased wear of moving parts
- greater risk of system failures
An oil change without flushing does not address the cause, but only part of the symptom.
Cleaning before an oil change: the correct order
Professional oil system cleaning/flushing before changing the oil ensures that:
- deposits and contamination is flushed and drained
- oil channels are clear again
- new oil can actually do its job
Only in a clean system can fresh engine oil provide optimum lubrication, cooling and protection.
Want to know more about the necessity of flushing? Read here
Preventive service instead of reactive repairs
For workshops, this represents a significant shift:
don’t wait until problems arise, but offer preventive service.
Flushing before oil changes:
- extends the life of engine components
- reduces the risk of consequential damage/repairs
- increases vehicle reliability
New engine oil is only effective in a clean engine.
Without prior cleaning, contamination and deposits remain, significantly limiting the benefits of an oil change.
A clean car starts with a clean engine
