Workshop Skills: Winter Storage
Our series on maintenance and servicing looks at the best ways to ensure your classic does not deteriorate in storage.
Winter hibernation for a classic car is one of the best means of protecting it from the perils of road salt, dirt and water that can contaminate the chassis legs, wheelarches and sills. However, it could be argued that similar damage can be inflicted upon it should the car be incorrectly stored. For instance, rising damp and moisture in the air can lead to corrosion, mice and other rodents may find their way into the interior and eat away at wiring and upholstery, or tyres may become misshapen and the battery could go flat. So a careful plan for storing your classic is essential.
Cleaning
The old saying that you should leave something in the condition that you’d like to find it surely applies to a classic car when storing it away for winter. And in this case it is not merely a preference, but also a means of reducing deterioration. Washing, cleaning and polishing the bodywork before you put it into storage may seem like a waste of time, but if you are putting a cover over the vehicle, this helps to reduce the risk of dirt becoming trapped and marking the paintwork. Even if a cover isn’t fitted, the inevitable dust will gather on the paintwork, and it’s much easier to wipe this off if the exterior has been polished. Adding a wax finish to the paintwork can help further, allowing dirt to be blown or gently wiped away with a microfibre cloth.
There are numerous types of car covers to choose from, depending on whether the
vehicle will be stored outside or inside. In all cases, it is wise to periodically remove the cover and allow the air to circulate. Perhaps you can run the engine too, but if you do fire it up, leave it running until it is properly warmed up to burn off any condensation inside the engine and exhaust. This also helps to reduce the risk of damp settling inside the car or unwanted animals moving in. For the ultimate in storage, a temperature- and humiditycontrolled environment is ideal, such as a Carcoon. This is a controlled bubble for the car, allowing filtered air to flow around the vehicle and just enough moisture to ensure rubber seals, leather upholstery and wood trim don’t dry out.
If a car cover isn’t going to be fitted and the vehicle is remaining outside, then there are a few preservation techniques to consider. Damp that settles on the ground will evaporate into the air, rise upwards and potentially settle inside the wheelarches and the undersides of the floors and chassis. Lining the wheelarches with cardboard can help to reduce this problem, along with placing a large sheet of cardboard underneath the vehicle and weighing it down with a few bricks (remember not to drive over them).
It's also important to be confident your classic will remain dry on the inside over winter storage, especially if it is stored outside. If your classic is prone to letting water in, then in an ideal world you will find somewhere under cover to store it and pay the premium this requires. However, we don't live in an ideal world so if this is simply not an option, at the very least consider removing objects that can get wet such as carpets, or if that’s not possible, add some newspaper to help absorb the unwanted water and change it regularly. Make sure any drain holes are clear by poking a screwdriver through them. These are often along the undersides of the sills, doors and chassis legs.
Seizure
Winter storage can result in a number of components becoming seized through corrosion, such as the bonnet release, handbrake and even the clutch. Some are more difficult to avoid than others. Leaving the handbrake off with the wheels chocked and a low gear selected (or P on an automatic) can help to preserve the handbrake. Applying a light grease to the bonnet release and any other similar mechanisms (such as the boot release) and even the door latches can help to reduce the risk of them becoming rusty over winter and difficult to operate. Even spraying such a grease inside key holes helps to keep them lubricated as they can also freeze when the temperature drops below zero.
Spraying a light grease over the handbrake mechanism, particularly if it’s located underneath the vehicle, will help to keep it free-moving. Some braking systems have a semi-mechanical compensator fitted for the rear brakes, which is operated according to the load being carried. This is worth lubricating as well to avoid seizure. Whilst a light grease may be suitable, a more longlasting product such as Prolan anti-seize grease may be better. This is designed to keep mechanical components moving and has been proven to last for up to 30 years, which saves time and money on multiple re-application. Based on lanolin, it is nontoxic and bio- degradable and can also be used in and around electrical connections to prevent moisture penetration and corrosion. A further advantage is that it also protects metal and rubber.
Battery maintenance
Trickle- charging the battery over winter is worthwhile, as a battery that goes completely flat may struggle to ever take a full charge again. If you don't have access to power at the storage site, then consider removing the battery and bringing it home to trickle charge, or to top up with a regular charger every couple of weeks. If the fluid levels inside the battery can be checked and topped up, do this as well, topping up with distilled water. (If you do remove the battery, remember on more modern classics that you may need codes before the stereo can be reactivated, and on some from 2000 or so onwards you may end up with ECU security issues if the car is left unconnected for an extended period.) If the battery is remaining with the vehicle, clean the terminals and apply petroleum jelly or the aforementioned Prolan anti-seize grease to protect them from corrosion.
Remember too that there may be other batteries to consider, such as a key fob, where a lack of use and another six months over winter may mean the small batteries inside need replacing. In some cases, the key fob will have to be synchronised to the vehicle by turning the ignition on and off a few times.
Tyre checks
Tyres can deteriorate over winter. Flat spots can appear if the vehicle doesn’t move, which may result in a knocking noise when driving the car. This will often disappear as the tyre’s shape returns when the car is driven, but there’s no guarantee, so it helps to move the vehicle periodically throughout storage. Tyre savers can also be used to help reduce the risk of flat spots. These look like wheel chocks, but provide a rounded surface for the tyre to sit on instead of the flat ground, thus reducing the risk of a flat spot developing. Under-inflated tyres put a greater strain on the sidewalls, so it’s wise to over-inflate them by 10-15% at the start of winter storage.
Check the manufacturing date of the tyres to see whether any will need to be replaced. A four- digit date stamp on the sidewall of the tyre will indicate when the tyre was manufactured – 1815 for instance means the tyre was manufactured in the 18th week of 2015. Most tyre manufacturers recommend their tyres should be renewed after six or seven years. If your tyres are at the end of their lives anyway, you might as well leave them on the car over winter, save up for a new set and take the wheels to a fitting station at the start of next season.
Fluids
The engine coolant must contain an appropriate quantity of antifreeze to avoid the risk of it freezing over winter. If you are unsure, test it with an antifreeze hydrometer (£5 and upwards from the likes of Machine Mart).. And if you are unsure what type of coolant has been added before, (or how old it is – mono ethylene glycol coolants only give full protection for two years) it may be wiser to drain and flush the system, then add a new product you know is suitable. This can avoid catastrophic results, such as mixing different chemistry coolants which react with each other, congeal and block waterways. Windscreen washer fluid should also contain a suitable additive, not only for more effective cleaning but also to protect it against freezing.
One aspect of vehicle storage that’s open to debate concerns the petrol in the fuel tank. Should it be drained or left full? There are several points to consider to help you decide. For instance, petrol generally loses volatility and goes off after three or four months. Although we’ve not come across any problems with using stale petrol, diluting it with fresh fuel is often the best approach, which means the tank should not be full. However, ethanol in modern petrol can extract moisture from the air, so some people prefer a full tank to limit the air in the top of the tank. But tanks never fill completely, so our preference would be to drain the tank before winter storage if possible, or to store it with a little fuel in (this will mean you can start and warm the engine up occasionally too) and then dilute this with fresh before driving in the spring.
Paperwork
The final points to consider before winter storage surround documentation. If the vehicle is still MoT tested, should you leave this to expire over winter, or have the car tested now so that it is ready and road legal for the spring? Forward planning suggests having an MoT test done prior to storage, but surely it’s better to have the car tested afterwards, just in case a problem develops over the winter due to the inactivity?
If you pay for your classic’s car tax (ie it’s not old enough to be exempt), then you may wish to SORN (declare statutory off road notification) it and save some money. And the same applies to your vehicle’s insurance, which in some cases can be changed to storage cover. Often, though, classic policies are so cheap that the cost of making any short-term changes is really not financially worth the bother – we were recently warned that making any change to a policy costing £82 would incur an administration fee of £50!