When you leave your car ‘home alone’

My new job will often take me away from home for extended periods, so I will not use my car for several weeks and sometimes a few months at a time. Will this cause any mechanical problems and, if so, what can I do to prevent them? Jos.

All car owners face this situation to some degree. If they go away on leave, or for work, or because the vehicle spends a long time in a workshop. And cars that stand idle do deteriorate over time. Some ill effects can arise after just a couple of weeks, and others may take months or years to become serious, but the process starts on day one.

The first and most frequent problem is the gradual discharge of the battery until it is flat. It may deteriorate beyond the possibility of recharge, and even if it can be resuscitated its capacity and lifespan will be reduced. The battery will discharge slightly even if all electrical items are switched off, mainly through conduction “leakage” from the terminals and via the dirt on the surface of the battery box. Your anti-theft device will also remain on, though usually consuming very little current on stand-by mode.

Preventive measures include ensuring the battery is fully charged when the vehicle goes into “storage”, and that its box is clean and dry. That should be enough if the vehicle is left idle for a week or two. If it will remain unused for longer than that, either the battery cables should be disconnected or a friend/neighbour should be engaged to start the engine about once a week while you are away and run it on fast idle (about 1200 revs) long enough for the temperature gauge to reach its normal operating position. Five minutes?

Using an external charger to regularly refresh and exercise the battery will equally look after the battery’s health, but that is all it will do. Running the engine to recharge is more beneficial because it also splashes fresh oil over all the inner working parts and stirs up the oil in the sump to prevent sludging. Also, when the engine approaches operating temperature, it circulates coolant through the water pump, the radiator and the jacket of cooling channels in the engine block.

These can all be prone to corrosion if the oil drains off metal surfaces until they are dry, and there is no irrigation and movement in the cooling system – especially if the coolant is plain (and possibly dirty) water. You should always use a good quality additive in your radiator, and keep it clean and up to strength, to inhibit corrosion and lubricate the pump.

Engine, cooling systems

Engines and cooling systems are not the only things that need to move to stay healthy.
Every moving part of a car benefits from at least some regular light exercise, where there are oil reservoirs (gearbox and diffs) it recoats all the surfaces and inhibits sludging.

On other parts, it stops grease from becoming too sticky and viscous and moves it around over the surfaces of bearings. And even bare metal parts that move through seals will be prone to corrosion and dust in humid conditions. Movement rubs off the first stages of oxidation before it becomes more deeply erosive.
So if you have a suitable friend or neighbour, as well as asking them to start the engine also get them to drive the car a short distance – even if just for a few metres – before parking it back in its storage place. 

This will also address another potential problem. Your tyres. If they stand absolutely still in the same place bearing the weight of the car for a long period, they can develop “flat spots” (permanent misshaping) where they are squashed against the floor. This can happen to any tyre, but those with steel-braced casings are most prone.

So for very long stand-stills, either drive them through several revolutions a couple of times a month to flex the tread and tyre walls, or at least ensure the tyres are inflated fully or raise the car body on blocks or stands so the tyres are not bearing significant weight.

For very long-term storage, the more extreme options become essentials. The car should be given the most thorough lubrication service possible before it is put away so all the oils and greases and other fluids are either absolutely new and clean or completely drained.

All of these hazards and remedies are more crucial if a car is old or in poor condition, but even brand-new cars suffer some degree of deterioration (ageing) if they remain part of dead stock in a store or showroom. Even their seals and rubber bushes can perish or become brittle. That’s why a car’s age starts from the date of manufacture, not the date of its first registration.

Beware, there is quite active global trade in dead stock between different markets, where a model that has long-remained unsold in one place is shipped to a showroom somewhere else as “brand new”.
That is legitimate, as long as traders declare what they have done, thoroughly overhaul old stock before selling, and offer a significant discount on vehicles which, though their odometers still read near zero, are in fact several years old. The manufacturing source and date are indicated on the VIN plate. If that (usually embossed or engraved to deter tampering) is changed or messy (or missing!) walk away.

The rumble could help ease the bungle

I see more and more rumble strips being installed on the approaches to our speed bumps. Thank you, thank you, thank you to whoever is doing that. They are a very useful warning of bumps that are mostly huge, unmarked and often difficult to see. But why do so many drivers slow down to walking speed when they drive across the thin warning ripples, and what can be done to stop this dangerous and disruptive habit? Wahome.

Short answer: There are three probable reasons why some drivers brake suddenly when they see the new rumble strips. One is that some of the strips are not shaped and sized correctly, and could cause damage or loss of control if taken at speed. Another is that some drivers have not been taught, nor learned by experience, that correctly installed speed bumps can be (and usually should be) crossed at normal speed.

A third is that some cars have suspensions/steering systems that are so defective that they cannot maintain control even when the strips are sized, shaped and spaced correctly.
So the remedies are self-evident. Every grid of rumble strips must be built to a single, specific and identical standard so motorists can be confident that they will cause no obstruction or disruption whatsoever to vehicles crossing them at any speed. 

Unless this is consistently achieved and assured, we will all learn the characteristics of the rumble strips on our regular routes and act accordingly, but any trip on unfamiliar roads will be filled with trepidation…as it already is with regard to the diversity of existing speed bumps.

Longer answer: We now have tens of thousands of speed bumps, and the majority are illegally high, illegally short, and ill-shaped. A large proportion has no warning signs and no markings. A great many are virtually invisible. They are expensive to build, disrupt traffic flow, exacerbate congestion both through increased journey times and tailbacks, add considerably to fuel consumption and wear-and-tear, and make both urban and long-distance journeys tortuous.

The number of accidents that they prevent can only be guessed. The number of accidents they cause can be measured, and it is high. The theory of well-designed and clearly signposted speed bumps as traffic “calmers” has definite safety potential. The practice of making them circa four times bigger than they should be, unmarked, in staggeringly large numbers, is actively dangerous. Even if the policy is somehow right, it comes at a significant personal price in time and money to every motorist, and amounts to an eye-watering national cost in infrastructure, fuel, congestion and lost productivity many millions of times bigger than that.
Rumble strips could help lessen those downsides and be a major blessing. If they are designed and installed and positioned correctly.

Rumble strips are a great solution where road signs and road markings do not exist or might not be clearly seen. They are a warning that there is a hazard ahead, and drivers should take special care and be ready to slow down AFTER they have crossed them. In Kenya, they could (indeed should) be usefully installed 70 metres or so before every speed bump!

Their vital advantage is that drivers do not have to “see” them in advance or at all! They do not need signs or markings. They are designed to be “felt” by the driver as an unmistakable but very mild vibration in the steering wheel, and they cause a momentary “rumble” sound from the wheels. They should not present any obstruction or disruption whatsoever to passing vehicles at any speed and should not require any change in normal motoring/cruising before they have been crossed.

If they are built incorrectly, with a shape or size that demands advanced action, or which disrupts the flow in advance, they contradict their very concept and core purpose and undermine their benefit.
Their whole point is that your eyes do NOT have to know they are there at any point in the proceedings, before, during or after.

Their message is delivered clearly but gently to your fingers, your bum and your ears – even in dark shadows or at night, even in pouring rain or any other conditions of the road, weather or traffic that compromise visibility - without the need for a sign or marking.

Rumble strips are used in the proper way all over the world and they are welcomed by all road users. In most places, they are built to an international design specification of shape, height and thickness of the strip, and the gap between strips. In most places, they have installed a consistent distance from an unseen hazard, so motorists know where the hazard itself is likely to be. And the hazard (whether it is a bump or a sharp bend or a dip prone to flooding or a pedestrian crossing or a junction on a brow) will also be signed and marked.

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