Insurance expert reveals hidden code you should know to prevent your car from breaking down this winter

Close up of car light in the winter

As we head into winter and the mornings become colder, giving your car a bit more love and attention can help to reduce the risk of breaking down during harsher weather conditions.

Car insurance experts at Howden Insurance have shared their top tips to prevent your car from breaking down this winter, including a hidden code that can tell you whether your car battery needs replacing, before the temperature begins to plummet.

Checking your car battery

Car batteries are one of the common causes of winter breakdowns due to colder temperatures affecting how well batteries are able to hold their charge. In fact, the RAC reportedly deal with more than 400,000 battery related vehicle breakdowns each winter.

A car battery typically lasts between 3-5 years, so determining its age can indicate whether it is likely to need replacing over winter.

If you purchased the car new, then the battery will have been brand new, and should be a similar age as the car itself. However, if you purchased the car second hand, you are unlikely to know the battery’s age, unless the previous owner or dealership provided you with this information.

If this is this case, the first step is to open your car’s bonnet and locate the battery. Some batteries will have a sticker on them which has a recognisable date format such as 4/21, which indicates the month and year it was manufactured. In this example, the battery was manufactured in April 2021, which would mean that it falls within the 3 – 5-year mark and is unlikely to need replacing just yet.

If there is no date sticker, check the battery cover or the battery itself for a heat stamped or engraved code, consisting of a series of numbers and letters.

The first two digits of this code indicate when the battery was made. The first digit represents the last number of the year that the battery was made, such as 9 for 2019. The second digit, which ranges from A to L, corresponds with the month it was manufactured.

For example, 1D would indicate that the battery was manufactured in April 2021. Different manufacturers may have these first two digits swapped around (e.g. D1), but it can still be decoded in the same fashion.

Letter and corresponding month Number and corresponding year 
A – January 2 – 2012 
B – February 3 – 2013  
C – March 4 – 2014 
D – April 5 – 2015 
E – May 6 – 2016 
F – June 7 – 2017 
G – July 8 – 2018 
H – August 9 – 2019 
I – September 0 – 2020 
J – October 1 – 2021 
K – November 2 – 2022 
L – December 3 – 2023 

If your battery relatively new but you’re still struggling to start your car in the morning, it could be due to making regularly short journeys that puts extra stress on the battery. Taking the car out for longer drives of around 30 minutes should help to recharge the battery to a more optimal state.

Make sure to also switch off anything that might put extra strain on the battery such as lights, wipers, the heater and radio before turning on the ignition.

Monitor your engine coolant

Engine coolant is a mixture of ionised water and antifreeze, that is added to the engine’s cooling system to prevent it from overheating. This addition of antifreeze prevents the water from freezing in colder temperatures of up to –15 degrees Celsius.

Your car’s engine coolant shouldn’t need regularly topping up, but if its lower than it should be, it could indicate that you have a leak, and this can put the engine at risk of overheating.

To check if your engine coolant level is low, make sure that your engine is switched off and that it has been allowed to cool for at least 30 minutes if the car has just been used.

Open your bonnet and look for a semi-translucent reservoir known as the expansion tank, which contains the yellow, green, blue, pink or red coloured coolant liquid. The coolant level should be between the minimum and maximum markings on the side of this reservoir.

To top up the engine coolant, use a product recommended by the vehicle manufacturer as detailed in the car’s user manual, and fill it up to the maximum line.

If you regularly need to top up your engine coolant, this can indicate that there is a leak in the cooling system, and this is something you need to get repaired by a mechanic, before it causes more serious problems.

Check your tyre pressure

Your car’s tyre pressure tends to more drop more quickly in colder weather, since the air condenses, and takes up less space in your tyres. Low tyre pressure not only leads to premature wear on the tyre tread but can also increase the chance of your tyres blowing out.

Make sure to regularly check the pressure on each of your tyres, to ensure that they are filled to the appropriate level. The correct tyre pressure for your vehicle can be found in your vehicle handbook, or on the inside of the fuel tank cap. Check your tyres for cracks, splits, or bulges in the rubber, as these can also indicate that they need replacing.

Check your tyre tread depth

It’s important to also keep an eye on the tread depth of your tyres, as ice and snow can result in tyres sliding and rotating more often, which can wear down the tread more quickly.

While the minimum legal tread depth in the UK is 1.6mm across the middle three quarters of the tyre, it is recommended to keep this above at least 3mm in wintery conditions.

You can accurately check whether your tyres meet the legal limit by using a digital tyre tread gauge, which will cost you around £12 from Halfords, or by using a 20p coin if you are in a pinch.

Place the coin into the tread grooves of your tyre, and check whether you can see the outer banding of the coin. If you can see the outside band of the coin, this indicates that the tyre is below 1.6mm tread depth and needs to be replaced immediately, as it is not road legal. If you cannot see the outer band of the coin, then your tyre is above the 1.6mm minimum limit.

De-ice your windscreen and wipers

Another common cause of winter breakdown is for cars to blow a fuse when operating the wipers if they are frozen to the screen with ice. Making sure to check that your wipers are turned off before the start of each journey, ensures that they don’t automatically try to clear the screen once the ignition is turned on.

If you anticipate colder mornings, covering your windscreen with an old sheet can prevent ice from forming. Using the wipers to keep the sheet in place not only prevents your wipers freezing to your windscreen, but it also reduces the need for defrosting the screen.


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