Took this from a post on the mk1 owners club forum:
It’s time to look ahead and decide what to do with your car over the winter months.
The ideal conditions in which to store a car are of course a dry garage, but it is still viable to lay up a vehicle under a car port or even off road in the open air – as long as you do it properly. A few hours spent on diligent preparation will save a lot of time and, quite possibly, considerable expense come spring time.
How many of today’s so-called barn finds, we wonder, were merely intended to be laid up for a few months but instead sank into a deep and deteriorating slumber before their eventual resurrection? So here goes.
1. Now is the time to change the oil and filter – before you put your car to bed. Old oil containing acidic material can damage your engine if left for a long time.
2. Drain and replenish the cooling system with the right proportion of water and anti-corrosion anti-freeze to cope with the coldest days of winter.
3. A spring clean. Yes, this really is the time to give your car a thorough wash and clean both on the exterior and interior, using a high-pressure hose to remove accumulated road dirt from the underside. A steam clean under the bonnet wouldn’t go amiss either and will aid inspection and repair of faults that you can attend to in the winter months. After this thorough cleaning, leave the car for a couple of days to allow all the water to drain away.
4. Apply grease to all mild steel brake and fuel pipes. This won’t prevent corrosion from the inside but will certainly stop corrosion from the outside.
5. It’s also a good idea to deal with any stone chips on the bodywork at this time before rust develops.
6. Petrol: Condensation forms inside empty tanks and causes them to rot through, so leave tanks half or more full over the winter lay-up. If the car is standing on its road wheels give it a bounce from time to time to slosh the fuel around the tank. If the car is to be laid up for a year or more, drain the tank completely as the petrol is likely to become stale (you can tell by the peculiar smell) and contaminated with water.
7. Prepare your garage or storage space. First make sure that there are no leaks then give it a thorough clean to remove dust and dirt which will otherwise migrate to the car. Make as much space as you can around the car to enable easy access and ensure that anything stored overhead is secure and won’t fall on the car. The more pleasant your storage environment the more likely you’ll be to pay frequent visits.
There are several other tasks that can either be tackled now or when the car is in position in its winter resting place. Our experience suggests that it’s best to do them now, because once the car is out of sight it’s also out of mind and jobs can be delayed, and then forgotten.
8. Apply a fresh coat of underside anti-rust preservative like Waxoyl.
9. Apply a good coating of wax polish to the bodywork, but don’t polish it off (when you put the car back on the road another coat of wax and elbow grease will restore the shine). Likewise treat bright work with either lacquer or a generous coating of wax or Vaseline.
10. Apply grease to all grease-points on steering, suspension and driveline.
11. Interiors: In the case of leather upholstery apply a good-quality hide food to keep it supple in its period of non-use. It’s also sensible to cover seats and floor coverings with dust sheets – if the place of storage is dry and airy. (Otherwise the dust sheets may help to harbour condensation and material-eating mildew). Don’t forget to lubricate mechanisms like seat runners, door and boot hinges, and hold-open devices, otherwise these may seize.
12. Screen wash: Drain fluid from pipes and jets and empty the reservoir. This not only prevents frost damage, but also the forming of sediment in the fluid as it stands.
13. Convertibles: Store with the hoods raised to prevent creasing, especially of rear windows, but also try to prevent direct sunlight from falling on the hood fabric or window plastic, as it will accelerate fading and deterioration.
14. Windscreen wipers: Either remove wiper arms or raise blades clear of glass by placing a match box or similar under each arm. This prevents the blade sticking to the glass or deforming unnecessarily. Note: don’t lift arms more than is necessary for the blade to clear the glass, or the arm tension spring may weaken.
15. Lights: Check all lamp assemblies for water or condensation on the inside. If in doubt remove lamp lenses (if possible) and dry out the interiors to prevent long-term condensation of bulb holders.
16. Radio aerials: Telescopic aerials should be greased if you intend to leave them retracted.
17. Door, bonnet and boot aperture seals: Smear a light coat of silicone grease or Vaseline on the seal faces to prevent seals sticking to paint surfaces.
BLOCKS OR WHEELS?
You have the choice of putting your car up on blocks or to leave it standing on its road wheels. If it’s simply winter storage it’s probably easier to leave it resting on its wheels as this will enable you to roll the car out on to your drive-way give it an airing from time to time.
If you choose this course it’s important to overinflate each of the tyres a few pounds per square inch above their normal pressures. REMEMBER TO CHECK TYRES REGULARLY.
Underinflated or flat tyres left bearing the weight of a car for any length of time will deform permanently and be ruined.
If you’re placing the car off the ground, first jack it up and then prop the car securely under its suspension on stout axle stands or substantial wooden block.
The preparation here is determined by whether the car is on blocks. If it’s on blocks the car won’t be moving during its storage period and the engine will consequently need special attention.
So, before putting the car away run it with some upper-cylinder lubricant such as Redex in the fuel. It’s also a good idea to trickle some through the carburettor air intakes to soften and clear any carbon deposits that may have built up.
With the car in its resting position remove the spark plugs and pour a little upper-cylinder fluid into each cylinder. Then, if your car has a starting handle, turn the engine over slowly a few times to spread the oil. On cars without a starter handle put them in top gear and push the car to disperse the lubricant. These simple precautions will help protect the cylinder walls and piston rings.
Remove the distributor cap and spray WD40 or similar silicone spray over the inside of the cap and contacts.
If the car is sitting on its road wheels there’s no need to take the above precautions providing you make a commitment to “exercise” it once a month or so.
Each time you give it an airing start the engine in the open and run it up to normal operating temperatures. This should take at least 10 minutes. Any less and you won’t be certain that any corrosive moisture in the exhaust system and elsewhere has completely evaporated. Drive the car backwards and forwards as far as the yard or driveway will allow, frequently exercising the brakes, steering and clutch. If you don’t have time to do this, you should at least turn the engine over, preferably with a starting handle. If the car doesn’t have one, remove HT lead from the centre of the coil and crank the motor over on the starter a few times.
BATTERY, BRAKES & ELECTRICS:
Battery: If the car’s going to be exercised as described above make sure you disconnect the battery between its regular airings. If the car’s immobile, remove the battery completely. Batteries deteriorate if left unused, so give it a trickle charge every couple of months or so. In the case of longer lay-ups of more than a year, the best way to preserve your battery is to deliberately run it down slowly every six months with a low-wattage bulb and then re-charge it fully from a trickle charger. Never allow a battery to stand when fully discharged or it may refuse to recharge.
Electrics: Treat the under bonnet circuits to a generous coating of water-repellent spray, particularly the ignition system.
Brakes: Leave the handbrake off. If the car is on the floor either leave it in gear or chock the wheels.
Inside: The car is now ready to be positioned in its resting place. If it’s a dry airy garage wind down each of the windows half an inch or so, and if there’s any fabric in the interior, such as a wool-cloth headlining or carpets, place a few mothballs inside. Mice and other rodents can also nest inside your car and very quickly ruin perfectly good seats. If the seat squabs are removable you can tilt them up (or even store them in your house if there’s room). Also consider placing a humane rodent exterminator in or under your car. Finally, cover the bodywork with dust sheets. Make sure these are suitable: i.e. cotton-based and not of the type to hold moisture.
Outside: If you’re compelled to store your car outside use a plastic cover, but with an interlayer of soft material like old sheets. Plastic alone will abrade the paintwork, especially if the cover flaps around. In any case lash it down tightly or the wind will soon reduce it to tatters.
As well as keeping moisture out, plastic keeps it in, so it’s essential to give the car an airing as often as possible whenever the weather permits. This free circulation of air will really help the car to breathe and stay fresh.
Even with these precautions your car still needs some attention during its winter lay-up. We’ve covered battery maintenance already and exercising a car that’s resting on its wheels. But it’s still important to give a car on blocks an airing from time to time. On fine days, when you get the chance, open the garage, remove the dust sheets and open the windows or doors and allow fresh air to circulate around the car for a while. Finally, when you shut the garage again, don’t lock the family cat inside!
Your car may be off the road, but how secure is it from both theft and damage? The storms of 1987 and the heavy snows of 2010 produced many horror stories of uninsured cars being damaged under collapsing garages and car ports. We hope coming winters are free from such catastrophes but there’s still a chance of accidental damage from falling objects. Likewise, we’ve heard sad tales from owners who’ve discovered the theft of a cherished vehicle sometimes months after it was stolen.
Our advice is to make your storage area as secure as possible, inspect your car regularly and keep it insured. It may cost a little more, but that’s nothing compared to the expense and misery uninsured owners can suffer as a result of theft or damage.
Some good tips here.