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The good oil


The good oil

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Long service intervals are only feasible if your car is being driven under ideal conditions.

Today's sophisticated multivalve engines, and advances in oil technology, have led to much longer service intervals for new cars. In some cases, car manufacturers confidently claim that servicing is only required at intervals up to 15,000km.

But many drivers are risking engine damage and premature wear by taking these claims at face value. You have to read the fine print to understand that long service intervals are only feasible if your car is being driven under ideal conditions.

Your owner's handbook probably contains advice suggesting that, if you drive your car under adverse conditions, you need to change the oil and get it serviced more frequently. Adverse conditions are not necessarily restricted to a Simpson Desert crossing. Most of us actually drive our cars in an environment that is extremely hard on the engine's oil. Mitsubishi suggests the following situations require more frequent oil changes. Most other car makers have similar lists:

  • Frequent short runs (for example, the average trip being less than eight kilometres).
  • More than 50 per cent of your driving in heavy city traffic.
  • Sustained high-speed driving in temperatures above 32 degrees.
  • Driving in dusty, sandy or salty conditions.
  • Continuous operation at higher than normal loading, especially towing.

According to Castrol, today's engines generally last about 200,000km. If they are well looked after, particularly in terms of regular oil changes, they can go up to 500,000km without a major overhaul. You would expect an oil company to encourage more frequent oil changes, but Castrol's point is a valid one.

Why change your oil?

Water vapour, unburnt petrol and gases from the engine's combustion process all end up in your oil.

If you rarely travel more than 20km after each cold start, your oil will soon become saturated with contaminants and lose its protective abilities.

This applies no matter what quality of oil you are using. In winter, the detrimental effects of short trips on engine oil are more severe.

It's only after 20km that the engine and oil get hot enough to vaporise these contaminants; this is why a car that is mainly used on long trips actually gives its oil an easier time.

So how often should you change your oil to ensure the best performance and reliability from your engine? Castrol suggests that if you travel less than 20km per trip for more than half your journeys, every 5,000 to 7,000km is recommended, or every six months if you cover less than this.
Always use a quality oil that matches the manufacturers specifications.

So if it's been a while since you checked or changed your oil, it's probably time to take some action.

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