How cold weather affects cars and what you can do about it

The arrival of a sudden cold snap puts you and your car under extra strain. This is one reason why break-down recovery services tend to be at their busiest during winter.

If your car has stood outside throughout a cold night, you will have several preparation tasks to fulfil, before driving off. Your car will also act and feel differently for at least the first few miles of your journey.

GEM's technical department, therefore, describes what you need to consider before setting off and what to expect, once on the move.

Before setting off

Should you anticipate a cold spell, there are a few tasks you can do in the evening to save you time in the morning. Covering the windows to protect them from frost is a good idea, as is giving the door seals a light dusting with talcum powder to discourage the doors from freezing shut.

When faced with an iced-up car, first thing in the morning, clear the glazing thoroughly. You can use chemicals (not engine antifreeze, which will damage the paintwork), a scraper, or even cold/lukewarm water. While the latter method is quicker, consider that it could freeze on the floor later and cause a slip hazard.

Apart from clearing the windows, so you can see out, do not forget to de-ice the exterior lamps, so road users can see you. Many lamps possess plastic covers, so be wary of scratching them. Strong chemicals and also discolour the lamps.

If it has been snowing, remove as much as possible from the car's horizontal surfaces, so it cannot fall into the path of other motorists.

Frozen water droplets are sharp and can damage the windscreen wiper blade rubbers, should they be dragged across them. Therefore, remove them before driving off.

Windscreen wipers can freeze onto the screen. Activating the wipers not only risks damaging the blade but also the motor. You may also blow the windscreen wiper fuse. Therefore, ensure that the wipers are free.

Even if you have filled the screen-wash bottle with a solution strong enough to withstand the cold without freezing, it will be of little use if the washer nozzles are frosted up. Pour lukewarm water onto them and ensure that the washers operate after you have cleared the windscreen and unstuck the wipers.

Before starting the car, switch on the ignition and wait for around 10 seconds, so all the car's various systems can power up. If our car possesses a diesel engine, wait for the 'coil' glow plug light to extinguish.

Depress the clutch before operating the starter motor. This reduces strain on both the battery and the starter.

Should your car be a modern fuel-injected vehicle, do not depress the accelerator. This will cause the engine to race before the oil has the chance to reach the areas that it is meant to protect. This situation causes unnecessary engine wear. Allow the engine to idle for at least ten seconds, before moving off.

We do not recommend letting an engine run at idle speed to warm it up, while you defrost the windows. It not only wastes fuel and leads to rapid engine wear but also might invalidate your insurance.

Once the engine has started, you can activate the heating and ventilation system defrosters. Consider that, on many cars, the heated rear windscreen function also defrosts the door mirrors, thus saving you this fiddly task.

Select dipped headlights (switch on fog lamps only in foggy conditions) to help other road users see you.

What to expect in cold weather driving

Modern car engines are designed to heat up as fast as possible. You may notice that the idle speed is higher than normal and that the engine revs take longer to fall. Your automatic transmission may also act differently to facilitate a fast engine warm-up. The car will act more normally as it reaches its preferred operating temperatures.

While Battery Electric Vehicle ranges fall dramatically in cold weather, so too does petrol and diesel engine efficiency. Therefore, expect your fuel consumption to increase.

So the cabin warms as quickly as possible, select the 'recirculation' function on your heater control panel. If you find that the interior is starting to mist, select the fresh-air setting again.

Air conditioning tends not to operate in cold weather, so you cannot benefit from its dehumidifying advantages in very cold weather. This is to protect itself from freezing up.

As batteries are put under considerable strain in the winter, your start-stop function might also stop working, until it detects that the battery has been replenished adequately.

Many automatic transmissions possess a 'Winter' setting to reduce the risk of wheel spin. Check if your car has this feature and be familiar with how it functions.

LCD and touch screens can become sluggish to react, until they warm up. This is normal.

Most UK drivers fit their cars with summer-grade tyres, meaning that they will have reduced grip in temperatures below a nominal seven degrees Celsius. Adapt your driving style accordingly.

When on the move, the gear oil will be relatively thick, making the gear selection stiffer. The transmission may even refuse to make a downshift into lower gears, when cold. Instead of applying excessive force to the gear-lever, reduce your road speed, or double-declutch, before making the selection. The gearbox will become more compliant, as the oil warms and thins.

Windscreen wipers can judder across the glass on cold mornings, caused by the rubber stiffening. Warming the screen with the interior defrosters, or the heated front windscreen function (if fitted), should alleviate the issue as your journey progresses.

Avoid revving the engine hard when it is cold. The oil takes much longer to warm than the coolant and cannot protect the engine adequately if it is subjected to high speeds and high loads, when it is still cold. Generally, keep engine revs below 3,500rpm.

We do not recommend disabling your traction control, when on the move. However, should you struggle to climb a small incline (such as a private drive) a small amount of wheel spin can help you.

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