Preparing Your Classic Car for Winter Storage

Choose the Right Spot Before You Do Anything Else

Winter storage is really an exercise in slowing down decay. Every tip below is about removing moisture, movement and chemical degradation from the equation for four or five months, so that the car you uncover in March is the car you parked in November.

Start with where the car will sit. A dry, well-ventilated garage beats a damp one every time, and a damp garage beats a sealed plastic sheet over the paintwork. If your only option is a concrete floor, lay down a plastic vapour barrier or a couple of sheets of heavy-duty polythene, because bare concrete wicks moisture upward all winter and that moisture finds its way into the underside, the brake discs and the exhaust. If you can, park on offcuts of timber or rubber matting rather than directly on concrete.

Finally, before you back it in, take it for a proper run of at least twenty minutes. Everything below works far better on a car that is fully warmed through and dry.

Wash, Dry and Wax the Bodywork

Grime holds moisture against paint and gives corrosion a head start, so a thorough wash is not cosmetic housekeeping — it is protection. Work from the roof down, use a dedicated car shampoo rather than washing-up liquid, and pay particular attention to the wheel arches, the sills, the underside of the bumpers and around the boot seal, where road salt collects and quietly eats metal.

Once it is clean, dry it properly with a microfibre towel or chamois. Do not leave water sitting in panel gaps or behind the chrome, where it will find its way into seams and start rusting from the inside.

Now wax. A decent carnauba or synthetic sealant gives you a sacrificial layer between your paint and the winter air. Two thin coats, applied panel by panel and buffed off before they fully haze, will see you through to spring. While you are there:

• Clean and treat chrome and stainless trim with a metal polish, then a light smear of wax.
• Feed rubber seals around doors, the boot and the windows with a silicone or glycerine stick so they do not dry out and stick.
• Touch up any stone chips with a matching paint pen — a bare chip becomes a rust blister over winter.
• Clean the glass inside and out so condensation marks do not etch into it.

Fuel, Fluids and the Engine

Modern petrol begins to oxidise within weeks, and the resulting gum and varnish are the enemy of carburettors, fuel pumps and injectors. Add a fuel stabiliser to the tank before you put the car away, then run the engine long enough for the treated fuel to circulate all the way through the system.

Fill the tank to the brim while you are at it. A full tank leaves almost no air space, and it is the air space that allows condensation to form inside the tank in cold weather. If you own a diesel, the same principle applies, along with a suitable additive to guard against microbial growth.

Change the engine oil before storage rather than after. Used oil carries acids and combustion by-products that will sit against bearing surfaces all winter. Fresh oil, plus a new filter, gives internal components the cleanest possible environment. Check the coolant strength with a hydrometer — a fifty-fifty mix of antifreeze gives you protection well below anything a British winter can throw at you — and top up the brake and clutch fluid if either is low. If your brake fluid has not been changed in three or four years, do it now; it absorbs moisture over time and that moisture corrodes callipers and wheel cylinders from the inside.

Take the spark plugs out, pour a teaspoon of engine oil into each cylinder and turn the engine over by hand a couple of revolutions, then refit the plugs. This coats the bores and stops rings seizing to cylinder walls.

Battery, Tyres and Brakes

Disconnect the battery, taking the negative terminal off first, and store it somewhere frost-free. Better still, leave it in the car connected to a smart maintenance charger that will keep it topped up without boiling it dry. A battery left flat in a cold garage will often not recover by spring.

Tyres develop flat spots when a car sits for months under its own weight. Overinflate them by around ten psi above the normal road pressure, or better still take the weight off by putting the car on axle stands — never on the suspension, always under a suitably strong structural point. If you must leave it on its wheels, roll the car a few inches every few weeks to change the contact patch.

Leave the handbrake off. Handbrake shoes and pads can bind to drums and discs if left applied for months, particularly in a damp garage. Leave the car in gear instead, chock the wheels, and if it is a manual with a clutch, press the pedal occasionally to stop the plate sticking to the flywheel.

A Breathable Cover and a Little Winter Housekeeping

Never use a plastic tarpaulin indoors. It traps moisture underneath and does far more harm than good. Use a breathable cotton or multi-layer cover designed for indoor storage, and make sure the car is completely dry before it goes on.

Inside the car, place a couple of moisture-absorbing desiccant trays on the floor and leave a window open a finger's width to allow air to circulate. Mothballs or a proprietary rodent repellent in the boot and footwells will discourage mice from making a nest in your wiring loom. Leave the heater and ventilation controls set to open, put a note on the steering wheel reminding you what you disconnected, and lock up.

Then check on the car every few weeks. Feel the cover for damp, glance underneath for drips, top up the charger if needed, and resist the temptation to start the engine for a two-minute idle — that brief run does nothing but fill the exhaust with condensation. Either leave it alone entirely, or take it out for a proper warm run on a dry, salt-free day. Come spring, it will thank you.