Getting dirty – practical considerations
Avoid skin contact with used engine oil. While regular exposure is thought to increase the risk of cancer, localised irritation is a short-term risk. If draining the oil after driving the car some distance, take care as there is a risk of scalding. Even experienced Diyers misunderstand simple dipstick marks. While the lower notch represents the minimum level before engine damage will occur, exceeding the maximum level is also likely to cause harm. If you are lucky, the excess lubricant might be forced from the engine through the oil seals. However, in some cases, oil can enter the combustion chambers – on diesel engines, this can cause the engine to run uncontrollably at excessive speeds, often to destruction. While all engines consume oil, many Dpf-equipped diesel cars are designed to raise their oil levels. This is because a quantity of diesel enters the sump and contaminates the engine oil during DPF regeneration cycles. Therefore, if you are working on a modern diesel car and adding the recommended quantity of oil does not bring the sump level to the maximum mark on the dipstick, resist adding more, because you could be removing capacity in the sump that is needed by diesel fuel. Apart from sump capacity, manufacturers and their lubrication partners consider how diesel contamination affects oil performance. While certain models (such as some BMWS) lack fixed oil drain intervals, preferring instead to have an oil condition monitoring system, remember that engine management algorithms will inhibit DPF regeneration if the oil’s protective qualities have reduced to a certain level. Therefore, resetting the service interval after performing an oil change is critical.