Show Me, Tell Me: Oil Pressure

"Tell me how you would check that the car has sufficient oil"

The engine oil lubricates the moving parts within the engine, Over time, it becomes thinner and dirty, and so less effective; it should therefore be changed at the manufacturer's recommended interval, which is typically every 12,000 miles, or every twelve months.

In between changes, the level may go down, through evaporation, leaks, or just by being burnt off by the engine; if it gets too low, the engine may be severely damaged. I would recommend that you check it every three or four weeks, and definitely before a long journey.

On a typical car, you check the level with a dipstick. If you have just driven the vehicle, then first let it stand for ten minutes, so that the oil that has been sloshing* around the engine seeps back down to the bottom; otherwise you will get a false low reading. Locate the dipstick, which will often be yellow:

Remove it from the engine and wipe it clean with a lint-free cloth; you will then typically see a hatched area, with marks for maximum and minimum levels:

Now it's clean, dip it back into the engine, the same place you just removed it from, and then pull it out again; you will now see the oil level, which should be between the maximum and minimum levels:

In this case, it's just barely ok, and it needs to be topped up. Add no more than a litre, then again wait ten minutes before checking again. Never fill above the maximum line! If there is too much oil in the engine, it will build up unsafe pressure, and the engine could explode.

It's also worth taking note of the colour of the oil. When it's new it will be a pale amber; the darker it gets, the closer you are to needing an oil change.

Having said all that, on an increasing number of modern cars the central computer has you covered. On my tuition vehicle, the Peugeot 308 Allure, the oil status is displayed on the dashboard when the engine is started from cold:

If it were low, it would say so!

The official answer to the question is:

"Open the bonnet, Identify dipstick/oil level indicator, describe check of oil level against the minimum and maximum markers."

However, the answer you give should relate to the car you are using for the test, so for mine, it is perfectly acceptable to say "When the engine is started from cold, the oil level will be displayed on the dashboard."

*this is a technical term :-)