Winter driving is not just about winter tires. By switching to “winter” gear, you will definitely not have to worry about preparing your car for the most demanding operating period. There are a lot of details that you need to focus on in order to make it through the winter with your car without any worries. Most people will deal with the car battery again, but there are more necessary actions to check.

The flashlight will let you down at the least convenient moment

Although it is precisely the cold morning starts when the car battery most often betrays you, its reduced performance is not to blame for frost, but too high temperatures in summer. However, the weakened battery cannot handle the morning start of a frozen engine with congealed oil, which also requires a lengthy warm-up (if it is a diesel).

You can check the current state of the battery yourself with a multimeter. It is ideal when the voltage at the battery terminals shows 12.5 to 12.8 V. The value of 12.2 V is the minimum. But the home multimeter does not tell much about how the battery will withstand the high load during starting. The overall condition of the battery can best be verified with a load test, for which car repair shops have a special device.

Photo: Škoda Auto

Even if you can measure the battery at home, you probably don’t have the equipment for a stress test. They will do it for you at the service center and you will know right away if yours will survive the winter.

You can help the battery in winter by limiting the use of comfort appliances such as seat and window heating, independent heating, as well as fog lights and other equipment elements that consume more current during frequent short trips. After a demanding start, the weakened battery is not enough to recharge after a short journey. Also manually turn off the stop/start system if your car has one. A normal battery needs a long drive, perhaps 50 km, to be sufficiently charged. It can take even longer for cars with variable charging.

It is also a good idea to check the charging, as alternators in more used cars may already show a decrease in efficiency. The optimal condition is when the alternator is charging with a voltage of 13.8 to 14.6 V. Some cars can show the charging value via the on-board computer (eg American cars and some older Mercedes), but only measurements and diagnostics can reveal the exact value. Even some universal diagnostics that can be controlled via a mobile phone can show the current charging values ​​while driving.

That you buy a new flashlight and you’re done? This does not have to be a self-saving solution. It is necessary to properly diagnose the cause and find out if there really is a problem in the alternator or, for example, in the electrical installation of the vehicle. Rapid self-discharge may occur. Also remember that in many modern cars, it is necessary to so-called register the new battery through diagnostics, so that the car knows that it has a new battery and learns to recharge it correctly.

So that your radiator does not freeze

Even in winter, the car must cool well and have the entire cooling circuit in order. Have the coolant checked to see if it can withstand frost. The minimum for Czech conditions is -20 °C, but of course it is better if the liquid has a reserve and does not solidify even at minus thirty degrees. It is checked with a hydrometer and you can easily buy your own.

Photo: Dalibor Žák

The freezing resistance of the coolant can be checked very easily and quickly using a hydrometer. Even in milder conditions, the temperature can drop to -20° C for a few days a year, and in some places it is quite regularly even minus thirty. Get ready for it.

If you have a problem with the loss of coolant and you have to add mixture or water regularly, remember that by adding water you are diluting the fluid and reducing its ability to withstand freezing. In severe frosts, the liquid can really freeze and destroy the engine. If you decide to change the fluid, pay attention to its correct specification. Some services don’t bother with this and pour whatever they have on hand into the car. However, you should always use only the type of fluid that is approved by the car manufacturer.

A thermostat is also part of the cooling circuit, and it becomes a source of unpleasant problems in modern cars. It regulates the flow of coolant and if it gets damaged or fatigued it will stay open and keep the car cooler than needed. It may happen that it does not warm up to operating temperature at all. This is especially problematic for diesels, which do not need to start regeneration of the particle filter and it can soon become clogged and irreversibly destroyed. But it also threatens gasoline engines. They can run on a rich mixture for a long time and this can destroy the expensive catalyst.

Foto: Shutterstock / Stason4ik

A leaking water pump or a malfunctioning thermostat are quite common problems in older cars. For cars with belt drives, the water pump is usually changed with them at prescribed intervals. The thermostat changes independently when it is not working. Some cars may have more than one thermostat, and as coolant temperature gauges are disappearing from cars these days, you may not know at first glance that something is wrong.

Also pay attention to the air conditioning. Even if you don’t have to cool the interior in winter like you do in summer, functional air conditioning helps with drying the air and demisting the windows. By the way, keep the windows clean, not only from the outside (new wiper blades are also like an original part for a few hundred), but also from the inside. The tinted glass throws reflections and then you can’t see anything when driving against the low sun or the lights of oncoming cars. Do not smudge the window with a tissue, take a clean microfibre cloth, a glass cleaner and give yourself at least five minutes to thoroughly clean the window.

Also add antifreeze to the washers in time. Use up the summer one and top up with one that can withstand at least -20 °C. Of course, if you have experience of frequently experiencing severe frosts, use an even more resistant liquid. Stock up in advance for the winter, so you don’t buy overpriced washer fluid at gas stations near highways. We also wrote about how to choose the right washer fluid in a separate article.

And when did you change the fuel filter?

So tires, coolant check, washer antifreeze. That’s probably enough. Or not? Of course, there are more things to check, and some cars have other sensitive elements that can surprise the user unpleasantly in winter and frost.

Photo: Dalibor Žák

Diesels in particular are quite susceptible to the quality and cleanliness of the fuel filter. In severe frosts, diesel fuel can easily “freeze” here. Fuel filter heating is not standard on all diesels.

For diesels, the fuel filter is an important part of the entire system. Diesel filters are larger, usually located in a separate holder (unlike gasoline engines with small filters directly on the fuel line under the car). Similar to oil filters, either an encapsulated type or a paper insert is used.

The fuel filter is primarily intended to prevent the penetration of dirt from the tank into the fuel line, but it also cleans the fuel itself, which may be contaminated. Tiny metal particles, dust, water and other impurities can cripple very sensitive and expensive diesel injectors. But the fuel filter in diesels is also a place where the diesel can “freeze” (paraffin crystals form and reduce the permeability of the diesel so that the car will not start). Not all diesels have heated filters.

Service events will help you save

You could do a thorough inspection and preparation of the car before winter yourself, but you have to be a big enthusiast to have the necessary workshop equipment. And since most of us do not have diagnostics, a jack and the necessary tools and preparations at home, it will be better to leave it to the service.

Photo: Škoda Auto

As part of a thorough service inspection, every service will find something that would be good to repair. But if you go to the service center regularly, usually only routine work and maintenance is done. Did you know that drum brakes, for example, need to be thoroughly cleaned every year? When was the last time you did that?

However, you can also entrust the inspection of the car before winter to a branded service. Every year, some car manufacturers come up with service events at discounted prices, and in addition to a complete inspection of the car before the winter season, including, for example, the mentioned stress test of the battery, they also offer discounted prices for necessary service work and parts, or even original accessories needed for winter operation.

Many car manufacturers also offer various “loyalty” programs for older cars (from four years old) through authorized service centers, which usually include discounts on work, cheaper original parts or discounted kits for the most common maintenance items, such as a clutch kit, distribution boards or brake linings and discs.