Dirty old oil will eat your engine
UNLIKE FINE RED WINE, ENGINE OIL DOES NOT GET BETTER WITH AGE
We’re all taught from the get-go to keep an eye on the oil in our cars but plenty of drivers are guilty of just topping up their oil rather than draining and changing it. What does this actually do to your car?
Not changing your oil over a long period of time can turn it acidic, leaving it to eat away at the surface components within your engine.
Unlike fine red wine, oil ages badly and over time it degrades whether it’s used or not. The process of oxidation occurs naturally in the oil but the rate at which this happens depends on factors such as temperature, moisture and oxygen levels, and engine condition.
In fact, short trips in cold weather could harm the oil more than frequent motorway trips because extended journeys allow much of the harmful build-up of moisture, unburnt fuels and acids to evaporate from the oil. The base quality of the engine oil can also play a factor in the aging process.
As the oil degenerates, it becomes thicker and darker due to the oil molecules reacting and joining together. As a result of the oxidation, acid begins to form which increases the risk of the component surfaces inside the engine being eaten away.
This is why changing your oil instead of just topping it up is so important. By draining old oil you remove impurities before any damage is caused and you also prevent engine components from becoming prematurely worn out. If your vehicle has missed services and your oil resembles tar, bear in mind that it may take a while to clean the inside of the engine to ensure any replacement oil stays effective for longer.
Cleaning out a clogged car engine comes with its own caution, however. It may cause existing wear to quickly reveal itself, which could result in expensive repairs. The schedule for oil change intervals can vary, but a lot depends on your style of driving. Due to the high quality of oils now available, most manufacturers recommend changing your oil every 15,000km or once a year.
Many cars now use a programme in the electronic control unit (ECU) to determine when oil needs to be changed. The reminder is based factors such as duration of use, ambient temperature, speed and acceleration. This is called condition-based servicing (CBS) and is an alternative to the common oil change intervals.
Owners who drive slower on long journeys may have more extended oil change intervals than those who drive faster on shorter runs without the engine fully warming up.
Some cars — generally the ones with a larger price tag — are even fitted with oil analysing or oil degradation sensors that measure the true condition of the oil rather than hazarding a guess.
With all these programmes and sensors, service stickers on our windscreens may very well become a thing of the past.