Storing Your Aceca Over Winter

Why the Aceca especially wants dry storage

Two features of the Aceca's construction make where you store it matter more than for an ordinary steel car:

• The ash-framed doors and hatch. Their wood absorbs moisture, and a car left in a damp garage for months can see it take up damp, swell and move, which loosens joints and, over time, shows up as doors that no longer shut cleanly. Damp is not just a rust problem on this car; it is a structural one.
• The alloy body. Aluminium panels do not rust like steel, but left damp against the car's steel structure they can corrode at the joints.

The single most valuable thing you can do for an Aceca over winter is keep it dry and ventilated, a dry garage, ideally with a dehumidifier or plenty of moisture-absorbing bags, is worth more than any other precaution.

The salt question, lay up, or pick your days

Winter road salt attacks alloy, chrome and the underside. The safest course is to lay the car up for the salted months. If you cannot bear to, only venture out on genuinely dry, salt-free days when the gritters have stayed home, and wash the car, underside included, thoroughly afterwards. A single damp, salty run can undo a winter's care.

Putting it away, the checklist

Do this over an afternoon before the first frosts:

• Clean and dry it thoroughly first. Storing a dirty or damp car traps moisture under the cover. Wash, dry, and wax the paint and chrome.
• Change the oil and filter. Old oil holds combustion acids that corrode internals over months of standing, fresh oil is one of the most important storage jobs. Run the engine afterwards to circulate it.
• Sort the fuel. Modern petrol with ethanol (E10, and even E5) absorbs moisture and degrades over a few months, gumming carburettors, a particular worry for the Aceca's triple carburettors. Either fill the tank and add a storage/anti-ethanol stabiliser (running the engine so it reaches the carbs), or store with ethanol-free fuel; some owners drain the float chambers.
• Check the coolant/antifreeze is strong enough for the coldest nights, a weak mix risks frost damage. A hydrometer tells you the freezing point.
• Battery on a conditioner. Disconnect it, or better, put it on a trickle charger/conditioner so it does not discharge, sulphate or freeze.
• Handbrake OFF, chocks on. Left on, the handbrake can seize and fuse the shoes; leave it in gear with wheel chocks instead.
• Tyres. Inflate to the maximum recommended pressure to resist flat spots, or put the car on axle stands to take the weight off tyres and bearings.
• Damp control inside. Silica gel or dehumidifier bags in the cabin and boot, a window cracked for airflow, and a breathable cover. Never a plastic sheet, which traps condensation.
• Keep the critters out: a plug in the exhaust and over the air intake stops mice nesting.

Mice, rats and a stored car

A car that stands in a garage from October to March is, from a mouse's point of view, a warm dry nest box with its own food store and bedding. The engine bay holds heat for hours after the last run, the air filter box and the silencer are sheltered tubes, and the seat foam, carpet underfelt and hood lining are nesting material. House mice can get through a gap of 5 to 6 mm, about the diameter of a pencil, so an ordinary up-and-over door with daylight under it is no barrier at all.

The damage they do

The expensive item is the wiring loom. Rodents' front teeth grow continuously and they gnaw to wear them down, and wiring insulation, fuel hose, rubber trunking and sound-deadening felt are all chewed. A loom that has been chewed in several places is a rewire, and a chewed fuel hose on a petrol car is a fire risk. Nests in the air filter box and the exhaust tailpipe are found when the car will not start or runs badly in spring. Carpets, seats and door trims are shredded for bedding, and the smell of a mouse that has died in the heater box or under the carpet takes a long time to clear.

An Aceca is a hand-built car with an ash-framed, aluminium-skinned body, and the cabin trim, headlining and the felt and wadding behind the aluminium are exactly what a mouse wants. The places to check are the air filter on the carburettors, the heater, the luggage platform behind the seats under the rear hatch, and the felt and insulation panels against the rear bulkhead. Re-trimming an Aceca is expensive, so the fortnightly torch inspection matters more here than on most cars.

Two further points worth knowing. Insurers commonly treat rodent damage as damage that happened gradually, which most motor policies exclude, and a UK Financial Ombudsman decision in 2018 did not uphold a complaint against Aviva, which had refused a claim for chewed engine wiring on exactly those grounds. And the story that modern soy-based wiring insulation attracts rodents is unproven; a US court dismissed a class action against Toyota on the point in 2018 because the owners could not show a defect, and Toyota said it knew of no scientific evidence that rodents are attracted to soy-based insulation. There is no reason to think an old loom is any safer than a new one.

What works

Keep them out of the building first. Seal gaps round pipes, cables and door frames with wire wool packed in and covered with filler or mortar, since mice will chew through foam, plastic and wood but not steel wool. Fit a brush strip or a rubber seal to the bottom of the garage door. Keep the floor clear, keep bird seed, pet food and lawn seed in metal or heavy plastic bins with lids, and do not leave bags of anything edible, including grass seed and bulbs, in the same building as the car.

Then make the car itself unwelcoming. Clean out every crumb before lay-up and leave nothing edible inside. Close the windows fully, or if you leave them cracked for ventilation, cover the gap with fine mesh. Bung the exhaust tailpipe and the air intake with a rag or a rubber bung, and hang a large label on the steering wheel saying so, because a forgotten exhaust bung is a classic spring mistake. Leave the bonnet up if the garage is secure: a cold, open engine bay is less attractive than a warm enclosed one, and you can see what is happening.

Set traps and check them. Conventional snap traps baited with peanut butter or chocolate, set against walls where mice run, are cheap and reliable, and a trap that has caught nothing in a month is useful information in itself. Check them weekly along with the car, and look for the signs: droppings the size of a grain of rice, shredded paper or felt, gnaw marks, and a musky smell. A fortnightly walk round the car with a torch, looking in the air filter box, under the scuttle, in the boot and under the seats, catches a problem while it is still one nest and not a rewire.

What is unproven

Ultrasonic repellers are widely sold and the evidence is mixed: one published single-house trial found fewer mice caught while a unit was running, but the general view of research bodies and pest control advisers is that rodents get used to the sound within days and that the devices are not a substitute for proofing and traps. Peppermint oil, dryer sheets, mothballs and cat hair are all repeated on forums; none has good evidence behind it, and naphthalene mothballs have not been legal to sell in the UK since 2008. By all means use them, but not instead of the measures above.

Poison

Rodenticide is a last resort. It is sold to the public only in small packs for use in and around buildings, it must be kept where pets and children cannot reach it, and a poisoned mouse often dies somewhere in the car, which is the smell problem again. If you have an established infestation rather than a single visitor, a professional pest controller is a better call than more bait.

Glue traps are banned for the public across Great Britain: in Wales since 17 October 2023, in England since 31 July 2024, where only licensed professional pest controllers may use them, and in Scotland since 1 July 2026, where sale and possession are banned as well. In England and Wales they are still on sale, which is not the same as being legal to use.

In spring

Before the first start, take the air filter off and look inside the box, lift the carpets and check under the scuttle and round the fuse box and loom for chewed insulation and nesting. Remove the bungs. If you find chewed wiring, trace it fully before switching on; a short to earth is cheaper to find with a meter than with a fuse.

Short version

Seal the garage with steel wool and a door strip, store nothing edible in it, bung the exhaust and intake and label the car, set snap traps and check them and the car every week or two, and treat ultrasonic devices and peppermint as extras rather than a plan.

During the winter

The debated question is whether to start a laid-up car periodically. The honest answer: a brief cold start that never reaches full temperature is arguably worse than leaving it alone, because it puts condensation and unburnt fuel into the oil without burning them off. So either leave the car properly prepared and untouched, or, better, on a dry, salt-free day take it out and warm it fully to temperature, exercising the brakes, clutch and steering, before putting it away again. Cars that sit stone-still for six months are usually the ones that need the most work in spring. Rolling the car a few inches occasionally also stops the brakes sticking.

Waking it up in spring

Reverse the process: check fluids and levels, look over the brakes and fuel lines (ethanol can perish old rubber over a winter), reconnect the battery, bring the tyres up to pressure, and, before the first start, consider cranking with the ignition disabled to build oil pressure before it fires. Then enjoy the first dry, salt-free drive of the year.

Common questions

Should I drive my AC Aceca in winter?

Best not on salted roads, salt attacks the alloy body, chrome and underside. Most owners lay the car up and only venture out on dry, salt-free days, washing it thoroughly afterwards.

How should I store an AC Aceca over winter?

Dry and ventilated above all, because the doors and rear hatch contain ash framing. Clean and wax it, change the oil, stabilise or empty the fuel, check antifreeze, put the battery on a conditioner, leave the handbrake off with chocks, and control damp with a dehumidifier and breathable cover.

Why does dry storage matter so much for an Aceca?

Its doors and rear hatch contain ash framing, which absorbs moisture and can swell or move in a damp garage, loosening joints and affecting fit. Damp is a structural risk on this car, not just a rust one.

Should I start my stored Aceca now and then?

A brief cold start that never warms fully can do more harm than good, adding condensation to the oil. Either leave it properly prepared, or take it out on a dry day and warm it fully to temperature before storing again.

How do I keep mice out of my classic car in the garage?

Seal the building (wire wool in gaps, a brush strip on the door), keep nothing edible in it, clean the car out, bung the exhaust and air intake and label the car, and set snap traps that you check weekly along with the car itself.

Do ultrasonic mouse repellers work?

The evidence is mixed and research bodies say rodents get used to the sound within days. Treat one as an extra, not as a substitute for sealing the building and setting traps.

Does classic car insurance cover mouse damage?

Often not. Most motor policies exclude damage that happens gradually, and a Financial Ombudsman decision in 2018 did not uphold a complaint about a refusal on those grounds. Check your policy wording.