Winter is hard on a car, and not only because of the frost. Thaws alternate with freezing nights, roads are covered in salt and de-icing chemicals, parking spots stay damp and snow and slush end up inside the cabin every day. This is when batteries go flat, doors freeze shut and tiny paint chips turn into rust spots.
The good news is that most winter trouble can be prevented with one weekend of work in autumn and a few minutes of care each week. Below is a plan that covers technical checks, the bodywork, the interior, rubber seals and mechanisms.
What you will need
Important: Do not apply lubricant or silicone to brake discs and pads, tyre treads or the windscreen. Work near the battery with the ignition switched off.
Step 1
Inspect the bodywork and touch up chips
Before the first frosts, walk around the car in daylight. Look for chips, scratches down to bare metal and orange spots, especially on sills, door edges, wheel arches and the edge of the bonnet. Over a winter, salt and moisture can turn a small chip into rust that goes right through.
Touch up fresh chips and have visible corrosion dealt with before the cold sets in. Unpainted metal parts and fixings under the bonnet can be given a thin coat of WD-40 Multi-Use: it displaces moisture and protects metal from rust.
Step 2
Check fluids, tyres and the battery
Replace summer screen wash with a winter mix and check the coolant level: the system must be filled with the type specified in the owner's manual. A spare bottle of screen wash in the boot is always useful in winter.
Tyre pressure drops in the cold, so check it more often. Winter tyres are needed once the average daily temperature stays below roughly +7 °C. Measure the battery voltage: a healthy battery reads about 12.6 V at rest and between 13.7 and 14.7 V with the engine running. If the readings are lower, see a specialist before the frosts. Clean terminals and connectors with WD-40 Specialist Contact Cleaner: it dissolves oxidation and dries without residue.
Step 3
Wash the body and underside to remove salt
Wash the car more often in winter than in summer. First rinse off salt and grit with a pressure washer so you do not rub abrasive particles into the paint, then wash with shampoo. Always rinse the underbody, wheel arches and wheels, as that is where salt lingers longest.
After washing, dry the car thoroughly, especially door openings, the fuel flap and mirrors, so the water cannot freeze. A coat of wax helps snow and dirt stick less to the paint.
Step 4
Protect the rubber seals
Door and boot seals stiffen in the cold, crack and freeze to the body. Clean off the dirt, let them dry, then apply WD-40 Specialist Silicone and spread it with a microfibre cloth. The silicone film repels water, so doors do not freeze shut even after a thaw. Repeat every few weeks.
Step 5
Treat locks, hinges and mechanisms
Lock barrels, door hinges and check straps, the bonnet catch and cable and the fuel flap mechanism all suffer from moisture that turns into ice overnight. Use short bursts from the thin straw of WD-40 Smart Straw on these points, work the mechanism and wipe off the excess. The product displaces water, lifts dirt and protects against corrosion.
Step 6
Keep the interior dry
Shake out wet mats after each trip and dry them indoors, otherwise moisture will mist up the windows. Vacuum the cabin, clean the windows from inside and check the cabin filter: a clogged filter makes misting worse.
Keep a scraper, brush and gloves in the car. Never defrost the windscreen with hot water, as the temperature shock can crack it. After a cold night let the engine run for a few minutes and avoid high revs until it has warmed up.
Tip: If the car is parked outside overnight, cover the windscreen with cardboard or a purpose-made cover and lift the wipers so the blades do not freeze to the glass. It saves time in the morning and protects the wiper rubber.
What next
Do the main preparation in autumn, then wash the car every week or two through the winter and repeat the treatment of seals and locks. A compact WD-40 100 ml fits in the glovebox in case a lock freezes anyway.
These uses come from the experience of WD-40 users in many countries. Always follow the instructions and warnings on the product label.
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