Checking Under the Bonnet

One reading tells you little. Two readings a month apart tell you a story. A coolant level that sat at MAX in March and is down at MIN in April has gone somewhere, and that is worth knowing long before a warning light tells you.

The Highway Code advises checking your fluid levels and tyre pressures weekly, and before a long journey. A useful habit is to note the date and where each level sat, on your phone or inside the handbook, so you have something to compare with next time. Comparing month to month never means waiting a month: a warning light, a new smell or a puddle under the car gets checked straight away.