What Car? Q&A - Do I need to top up my oil?

Q. I have a Ford Mondeo TDCi Ghia X 2.0-litre diesel auto, and I am led to believe that diesel engines need to be regularly 'topped up' with oil. Is this true?
Charles D White

A: All cars burn oil, whether they are petrol or diesel, so it's important to make regular checks of levels by using the dipstick, and top up accordingly to avoid potential damage whatever type of fuel you use. Don't rely on the oil light to tell you when you need to top up - it could be too late.

Park on level ground, wait ten minutes or so for the oil to settle back into the sump, and remove the dipstick (look in your manual to find out where this is in the engine bay). Wipe the dipstick clean, reinsert it and remove it for a second time to get an accurate reading.

Roughly speaking, a healthy engine should burn between 0.2 and 0.5 litres of oil every 600 miles or so. If your car is using a lot more than this, it's a sign that something more drastic could be wrong with the engine.