Exposing the myths of long term car storage – Winter preparation

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Exposing the myths of long term car storage – Winter preparation

Exposing the myths of long term car storage - Winter preparation

Europe was fortunate enough to experience a beautiful summer this year, but as the weather gets cooler, we might wonder where we could park the car for the winter. If only it was as easy as locking it up & walking away until spring!

Unfortunately, its damaging to leave your precious asset in one place for an extended amount of time – especially if your asset is a collectors item! That’s why its important to prepare your car for the long winter months on the horizon, so when spring time makes its return, your car will start up without any hassle and most importantly, look as good as the day you left it.

Thus, the question arises. How do I store my vehicle for an extended period of time, in a way that won’t deteriorate it? The internet bombards us with a variety of suggestions. This can be overwhelming instead of reassuring. Hence the reason I thought to write this article, to simplify the complications. The following tips are based on my own experiences that have been tried & tested and I recommend to my clients.

I’m writing this in Switzerland – where winter months are long, cold, wet and frosty. Driving in the snow may prove to be a challenge. In order to keep the roads from accumulating lots of ice, salt is thrown over the roads surface. This can cause severe damage to vehicle parts. Most people change over to winter tyres. Unlike in Germany, this is not yet mandatory in Switzerland, but if an accident occurs without having changed to your winter tyres, the chances of insurance covering the damage is really low. These, & many other risks, are the reason why some store their cars over winter.

Preparation is key!

Here are some steps to take before you choose to lock your vehicle away:


The number 1 rule is to have your car detailed before storage. It may seem counterintuitive to get the car washed and detailed before putting it away for months, but here are some reasons why this is so imperative. Dirt, brake dust, insects, bird droppings and even dried water drops that may have collected over summer that can permanently damage delicate car surfaces when left for long periods. Oxidation could also take place when not protected. This is a chemical reaction in which electrons are lost in the paint… “Drying out” and in extreme cases, leads to dulling of the clear coat or even a white chalky residue. A professional detailer will ensure that your car is decontaminated and protected using a high quality wax or sealant before storage.

If dust happens to settle on your car during storage, it can easily be removed if this step has been carried through.


This is an area often neglected. Most people think that a vacuum is all that’s required. Bacteria has left it’s footprint all over your car’s interior. Especially if you have driven long distances in the mid-summer heat. Who doesn’t love road trip snacks? But those little pleasures leave their mark! Crumbs & spills are inevitable, and wherever these have been left, a perfect, growing germ environment has also been left. The combination of this, humidity and bacteria leaves that “musty” smell in your car. In severe cases, mould grows which ruins your lovely leather. Preparation can go a long way in preventing all of this.

Clean all leather and plastic surfaces using high quality leather and plastic cleaning products. There are also great conditioning products on the market that prevents drying out and cracked leather. When using a conditioner, ensure the product is completely dry before closing your car’s doors for winter. You can speed up the drying process by using a hair dryer.

Some have a theory that you should not condition your leather before storage. They say in extreme cases, mould can use the conditioner as food, & grow on conditioned surfaces. I tend to disagree. If surfaces are correctly prepared, or, as just discussed, cleaned and dried before conditioning, the bacteria would have been killed. Conditioning leather over winter is a great way to keep your leather looking and feeling soft, as it always should be.

Humidity Control

To keep the humidity at a constant low inside your car, a dehumidifier is a must.

humityI use a German brand called ThoMar. It’s a great value for money bag filled with moisture absorbing granules. The bag is completely sealed, so there is no risk of accidental spillage that can mess your newly cleaned interior.

The bag can absorb up to 80% of its own weight in moister and is leak proof. It’s effective for about 4 months (perfect for winter storage) and can be reused over and over again by simply heating the bag on a radiator or airing it out in a drying room.  Don’t forget to drop one of these miracle bags into the boot.

Other dehumidifying systems are usually open in a large cup containing a powder that has to be thrown out after one use. Some recommend leaving your windows open about a centimetre or two to keep the air circulating inside your car. The problem with this is that it also allows dust and humidity to get in. It also creates the perfect spot for rodents (mice) to get in & use as a hiding place for winter.

Storage area

Storage areas vary vastly, but I have narrowed them down to two main areas:

  1. The super modern, fully heated, completely dry and dust free storage area that is specifically designed to store a collector’s car. I suppose it’s apt to call this a lounge, for you car. These are the best to option for as you don’t have the problems of temperature changes, dirt, humidity or rodents, all you need to do is detail your car and plug in a battery charger.
  2. Second type of storage is simply a secure garage, either above or below ground. It’s normally not heated, although temperatures rarely reach below 0°c (32°F). If it is a shared garage, other cars may be in & out which brings in more humidity, dirt and dust.  Storage in these areas can be a little challenging but still viable with the right steps.

If you can choose between the two, its wise to make the decision based on how long your car will be in storage for. (This is discussed in further detail below)

Fuel Tank

Your fuel tank should be left full. If your car is stored in an unheated garage, the temperature can change considerably during winter. When the tank is only filled halfway, condensation could form on top of the tank, and water mixing with your fuel can cause some serious complications.

Fuel matters

Petrol will stay fresh in a sealed container for about a year but starts to degrade in as little as a month when exposed to the atmosphere – the lighter more volatile fractions evaporate, lowering the fuel’s octane and making starting harder.

Petrol exposed to the atmosphere will start to oxidise over long periods too, producing gum and varnish deposits on fuel system components.  This is more likely to be a problem with older carburettor fuel systems than with sealed fuel injection systems.

Stored diesel should be OK for up to a year, depending on temperature but will start to oxidise over longer periods, producing gum and other sediments that can quickly block filters when the engine is run again.

Bear in mind that diesel fuel specifications change through the year – fuel bought in summer will be much more susceptible to waxing in cold weather than winter diesel formulated to give protection down to at least -15C.

Fuel tank

Unless you are able to ensure a dry stable environment, for periods over a month or so it is best to store a vehicle with a full tank of fuel to reduce the space for water to condense.

Condensation in the fuel tank can be a serious issue:

  • Corrosion can seriously damage the tank, though most modern tanks and fuel linesare plastic.
  • Current petrol contains up to 5% Ethanol which has an affinity for water. In extreme cases phase separation can occur where the Ethanol and water separate and drop to the bottom of the tank
  • Water allows bacteria and fungal growth in diesel which can require fuel tank removal and cleaning to eradicate.

For long term storage, particularly of older (pre-injection) vehicles, consider using a fuel stabiliser additive. Stabilisers are widely used for garden machinery, and other petrol-powered equipment left unused for a couple of seasons as well as motorbikes taken off the road over winter.  Follow the instructions carefully.

Courtesy of The UK Automobile Association

Should I consider a Fuel-Stabiliser?

This is a hot debate at the moment. I could write an essay about this topic.  In short, my answer is no. Fuel-stabilisers are best utilised on boats, lawn mowers etc. Owners use them when their vessel is not being used for a long period of time & kept in a moist area. Stabilisers can help prevent corrosion, which is not an issue for modern cars. They also help prevent Phase Separation should moister get into the tank.

Phase Separation is caused by ethanol combining with water into a solution called “crud”. This sinks to the bottom of the tank, taking the entire octane along with it. This is severely damaging to your engine. Fuel-stabilisers only help mitigate the effects of phase separation. In other words, if water gets into the fuel tank, you are still going to have crud at the bottom of your tank, whether you have a fuel stabiliser or not and will need to drain it anyway.

Still, to be sure, I asked Shell’s technical department in Germany what they recommend for long-term storage if using their fuel. And here is what they had to say.

We do not recommend any additives in our fuel. However filling the tank so that it is full is recommended for long-term storage. Large temperature swings in winter, over a 24 hour period (for example in an unheated barn) increases the risk of condensation in the fuel tank considerably…Our fuel should be safe to store anywhere up to 12 months. Shell’s “VPower” V100 (Octane 100) contains no Ethanol, unlike the Octane 95 where the law requires that Ethanol be added. Therefore there is an even smaller rick of Phase Separation”

Many thanks to Shell’s Technical Department for taking the time to explain.

Oil change

Some of my clients insist on changing the oil and filters before storage. It is beneficial doing this before rather than after storage. Used oil contains contaminates and can oxidize. Changing your oil will get rid of all the engine contaminants that may damage the engine if left for a long time (acidity build up). If the car is going to be stored for less than 3 or 4 months, it’s not necessary to change the oil, but is considered good practice nonetheless.


Antifreeze considerably lowers the freezing point of the coolant and also contains anti-rust additives. Most radiators contain antifreeze anyway but your windscreen washer is usually forgotten. It may sound odd to apply this whilst your car is not in use, but if the storage area has no heating and the temperature drops below 0°c (32°F) water can freeze in the pipes and pumps causing damage.


In the old days your grandfather would have jacked up the car onto blocks to prevent flat spots on tyres. Flat spotting happens when a tyre is compressed against a hard surface while the car is parked. A section of the rubber becomes stiffer than the rest of the tyre and these flat spots cause a noticeable disturbance when the car is in motion.

Today, flat spots are not a common issue. Modern steel-belted radials rarely get a flat spot and if they do (due to extreme temperature changes) they can normally be driven out within a couple minutes of being in motion. High speed rated tyres (H to Y-rated) on the other hand, are more susceptible to tyre flat spots, especially when parked on a concrete floor. Rubber on these tyres is designed for maximum road contact to improve handling, but are also unfortunately vulnerable to tyre flat spotting.

If you are worried about flat spotting, get yourself some tyre cushions. Home made solutions like carpets, sandbags or plywood under your tyres just won’t suffice.

There are specialist manufactures like Reifenkissen

Or Flatstoppers

If you want even more information about flat spotting on H-Y Rated tyres there is a great article written by Race Ramps here:

TIP: One preventative measure is to slightly over inflate your wheels by about 10-15bar, as the wheels lose about 2-3bar of pressure each month. Never raise your car onto blocks leaving the wheels to hang. Not only is it old fashioned & unnecessary, it also elevates the risk of damaging your car (pun intended).

Park break

I recommend leaving the parking brake off during long-term storage. The break pads tend to stick to the disks, especially when left for a long period without moving. If there is a risk of the car rolling while being stored because of unlevelled ground, I suggest getting a stopper to prevent rolling.

TIP: If you have used the park break over an extended amount of time, the breaks could seize. If so, try engaging a gear and driving slowly, otherwise dismantling may be necessary.

Tip : Roll the cover onto the car rather than pulling it.

Car covers (indoor only)

This is also a debated topic with car enthusiasts. Personally, I am not a fan of car covers for a number of reasons. But I have had situations where storage was so poor that I had to insist on my client using one.

Some reasons why I don’t like them is the risk of scratching, which increases greatly. All it takes is a single grain of sand to be dragged across the car when placing or removing the cover and the car has to be detailed again.

Also, if the car cover is not perfectly fitted, the movement of the fabric will rub off any protective wax or product way faster and damage the surface by scuffing. If you want to use a car cover, then I urge you to take precautions.

Only use the cover when you are absolutely sure the car is clean. Before using the cover for winter storage, wash it by following the washing instructions carefully. Never let it touch the ground, as this instantly picks up dirt. When putting the cover on, ask someone for assistance in order to prevent as much movement and stretching as possible.


Another nuisance that comes with winter storage are animals and insects. A garage is relatively warm and dry, and that is heaven for little creepy critters. There are plenty of places in your car for them to hide.

Preventative measures can include putting steel wool in the exhaust pipes and other openings. I have heard that putting peppermint oil around the perimeter of the car is also meant to keep mice away (If you’re not too concerned about staining the floor).

In Europe we have problems with Martens (ferret like animals) getting into our garages. Martens cause damage to soft plastic and rubber parts in parked vehicles. This costs millions in repairs annually in central Europe alone. This has thus lead to some companies offering marten damage insurance, “marten-proofing” and electronic repellent devices.
I have had personal experiences with these pests. My car was parked in a brand new underground garage (naturally vented) and these furry little “friends” managed to get into the engine bay & ripped out a whole bunch of my electronics.

Tip: Martens are territorial and can leave their scent in engine bay areas. Therefore, regular washing & upkeep should keep the engine bay as clean as possible. Rodent control products may also be necessary if you suspect you have a rodent problem.

Tip: If you are considering buying one, I recommend the self-supporting cocoon. The older models tend to deflate onto your car and have the potential to scratch it.

For more info on these cool inventions, go to https://www.carcoon.com/

Carcoons and bubbles

After discussing all the problems with humidity, animals, dust, scratches, covers etc., its enough information to make you want to pull your hair out. (I don’t have any left! But that’s for another article ☺).

So is there an alternative? Carcoon or Car Cocoons are becoming more and more popular.

What is a CUntitled-3arcoon? Well it’s pretty much a protective bubble, a mini-storage area for your car. Designed for infrequently used vehicles & super convenient for winter storage.  Although at first sight the cocoon looks strange, it’s a brilliant and simple design that addresses all the problems that long-term storage presents. The bubble is pressurised so nothing can get in as it is airtight. Insects and rodents have no chance of getting in and because the car is isolated from the constantly changing temperature and humidity, there is no condensation. Its squeaky clean inside, and the air is continuously circulating and cleaned by the use of carbon filters.  It even supports battery chargers for your car.

Charging your Battery

After your car has been parked and is nice and snug for the winter, don’t forget to plug in your battery charger.

There are various types of battery chargers currently available, most predominantly smart chargers and trickle chargers. However, smart chargers present a much safer and efficient way of maintaining and prolonging the life of your car’s battery.

With modern vehicles full of complex and sensitive electrical equipment that constantly draw current from the battery, an ever-increasing number of mechanical faults from new and older vehicles alike, are battery related. However, the expense and inconvenience of battery failure could be heavily reduced by regular battery maintenance.

Once a battery has reached its optimum charge levels, a trickle charger will simply send in a level of charge for a certain amount of time and then switch itself off, continually repeating the process until it is removed from the battery. These ways of charging your battery can potentially over charge it, causing it to dry out, or even start to leak gas, and ultimately kill the battery.

I’m a big fan of CTEK. They have a great range of chargers for every type of car and truck. They are easy to use, a “plug in and walk away” type of system. Their smart chargers move into a pulse maintenance mode once the battery is fully charged. Rather than sending in a charge and estimating the batteries needs, a CTEK charger will stay in constant communication with the battery, reacting and charging only when it is needed.

In pulse maintenance mode, the battery will be allowed to naturally self-discharge to a certain level before being fully charged once again. Not only does this form of battery charging avoid the risk of overcharging, but the battery is also being exercised as it would during normal use, thus the lifespan of the battery is extended considerably.

Cteck  http://www.ctek.com/int/en

In the old days people use to remove the battery when storing. This is really not necessary anymore. Older batteries were susceptible to leaking and boiling over, etc. But more modern batteries are very stable. Besides that, the electronics in your car need a power source. It’s an awful lot of work for very little gain.

Tip: One of my pet peeves with battery chargers are cables that scratch painted surfaces. A very simple and inexpensive way to prevent cables from chipping & scratching is to wrap a microfiber cloth around the cable wherever the cable is touching the car.

Watch to learn more

Should I Start my Car up Monthly?

Some feel that this is necessary, but is yet another myth. In the old days it was recommended to start your engine up, let it run to warm up and then switch it off. Today, it’s considered more stressful and damaging to the engine and components to do this. Do not start the car unless you are going to get all fluids to full operating temperature, which is hard to do unless you drive it. Idling your engine in winter is just going to create a lot of condensation, especially in your exhaust system and probably other components as well.


What If need to shift the car?

How do you move your car without starting the engine? Hydraulic car movers or a Car Dolly Auto Mover is great if you just need to shift the car a few meters in the garage without starting the engine.

The Dolly’s slide under the wheels and raise the car a couple of centimeters using a hydraulically operated foot pump. The position is locked into place with a pin and then you can safely shift the car.

Start-up After Storage

Staring a car for the first time when spring arrives is dependent, to some extent, on how well the car was prepared before being put into storage.

Tip: Some people find it helpful to leave a note on the steering wheel to ensure that you have not forgotten any of the following steps before driving.

  • If you have used a cover, remove the cover and wash it. When dry, store in an air/dust tight container so that it’s ready for next winter.
  • Remove the battery charger.
  • Check the engine bay and ensure that nothing is nesting under the bonnet or has chewed through pipes, hoses or wires.
  • Check all fluid levels before starting (Oil, Break, power steering etc)
  • Check the tyre pressures
  • Remove the humidity control bags from inside the car and dry them (I store the dried bags with the car covers)
  • Because the car has been detailed before storage the car should be spotless. If your car was left uncovered, gently dust the car off using a duster.
  • I also recommend adding another layer of wax before the season starts. Some wax products loose some of its protection and gloss after about three months.
  • Last but not least, spray on a little Zymöl Field Glaze.
Quick Summary :

Storing your car:

  • Thoroughly clean your car inside and out (a professional Detail is recommended)
  • Close all windows and place a couple of dehumidifier bags inside the car (including the boot)
  • Fill your feul tank to the brim (do not add fuel stabilizers)
  • Optional, change oil and oil filter before storage
  • Ensure the window washer fluid is suitable for winter and has Anti Freeze (do this before you clean your car)
  • H-Y Rated tyres should use cushions other wise not necessary
  • Leave the park break disengaged (Use stoppers if there is a risk of rolling)
  • Don’t use a car cover unless absolutely necessary (i.e. dirty environments)
  • Carcoon™ protective environments are highly recommended
  • Use a Smart Charger (rather than a trickle or battery charger) to keep your battery optimal
  • Do not start your car whilst in storage unless driving

Preparing your car for winter storage may seem like a lot of work, but the goal is to keep your car not only looking great, but running great as well. Nothing is more disappointing than seeing the first warm spring day and wanting to drive your prized possession and instead, you spend the day cleaning it. Or worse! Your engine doesn’t start…

If you still feel that this is too much prep work, here at Swiss Detailing we have specially designed packages to prepare your car for winter storage and get it ready for the road in the coming spring. We will inspect the storage area and optimise a solution for you and your car.  We are offering a special 20% discount on all bookings made before November 2015. Please use the quote “Hibernation” to receive your discount!

Stay Warm!


0adb082Stephan Graf is the founder of Swiss Detailing.

His passion is his profession: He details luxury cars and acts as a consultant for the owners.

Get more from Stephan on Facebook.

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