Tips & Guides

WD stands for Water Displacement and the 40 is the fortieth attempt at the formula, which tells you what it was built to do: push water off metal and creep into corrosion. It is not a grease, and using it as one on brakes, belts, seals, locks or headlight lenses causes real damage.

Ten grams out of balance throws about 2.5 kg of force at your wheel fourteen times a second at 100 km/h, which is why a lost balance weight is felt within a day. Where you feel the shake tells you which end of the car it is, and whether balancing is even the right fix.

State of health is the percentage of its original capacity a battery still holds, and it is worth thousands on a used electric car. The dashboard range figure is not it, and neither is mileage. Read the real number from the car before you agree a price.

Every EU registration certificate carries the same harmonised letter codes, whatever language it is printed in. Field B is the date the car was first registered anywhere, I is the date of this document, and a gap between them means an import, a pre-registration or a car that came back onto the register. Read those two before you read the advert.

Most fines drivers collect abroad are for paperwork rather than for driving: a missing vignette, no emission sticker, or a foreign plate nobody ever registered with the city. Austria's digital annual vignette is not valid for eighteen days if you buy it online, and Brussels charges 150 euro for an unregistered foreign car even when it was clean enough to enter.

The first ten minutes of rain after a dry spell give you the most slippery road surface of the year, because the shower lifts weeks of oil, diesel and rubber into a film instead of washing it away. Stretch the gap to four seconds, brake in a straight line and switch your dipped headlights on by hand.

A no-claims discount is not a reward for good behaviour, it is a multiplier applied to every premium you pay for years afterwards. One at-fault claim raises a French coefficient by 25 percent, costs a Dutch driver five claim-free years and drops a German driver four to six SF classes. On an average premium that adds up to more than a thousand euros, which is far more than most small repairs, and in most markets you can still change your mind after the claim is settled.

ISA is a warning system, not a speed limiter. It has been compulsory on every new car registered in the EU since 7 July 2024, it works out the limit from a camera and a map that regularly disagree, and the same law that put it there guarantees you can switch it off for the drive. It just will not stay off.

Brake fluid is hygroscopic, so it starts absorbing water the moment it is fitted. Roughly one to two percent a year is enough to pull the boiling point of DOT 4 fluid down from over 230 degrees to around 155, which is exactly where a firm pedal turns soft on a long descent. Two years is the interval that matters, and a falling level in the reservoir is telling you something else entirely.