Winter Car Checks: 10 Things to Do Before It Gets Cold

Most winter checklists are ten items of equal weight. They are not equal. Two of these affect whether you can see and stop. The rest affect whether you get there at all — and it is worth knowing which is which before you decide what to skip.

The two that matter most are also the two almost nobody does, because neither is visible and neither is checked at an ordinary service:

• Antifreeze concentration — not the level, the strength. Weak coolant can freeze and crack a cylinder head
• Battery state of health — not whether it started this morning, but how much capacity is left

Both take a couple of minutes with the right equipment and neither can be judged by looking.

The two nobody tests

Antifreeze strength. Coolant is not a fill-and-forget fluid. It does two jobs — it lowers the freezing point and it carries a corrosion inhibitor package that protects the aluminium in the engine — and the inhibitor depletes on a timetable whether or not any coolant has leaked.

A correct mix is usually around 50/50, which protects to roughly −37°C. That sounds like enormous headroom for Birmingham, and it is — but the number falls away sharply as the mix weakens, and a system that has been topped up with plain water two or three times over the years is a long way from 50/50. Frozen coolant expands, and what it cracks is the engine.

Testing it takes a minute with a refractometer. It is included in a major service and in nothing below that, which is why a car on interim and full services can go a decade without anyone checking it.

Screenwash concentration. The failure here is not dramatic, it is just badly timed. Summer-strength or water-diluted washer fluid freezes in the bottle and the lines, so on the first frosty morning you have no washers — usually on a salt-covered dual carriageway, which is precisely when a smeared screen becomes a visibility problem. Frozen fluid can also split the reservoir or kill the pump.

Mix it to the winter ratio on the bottle rather than the summer one, and never run plain water. Worth adding: an inoperative washer is an MOT failure in its own right.

The full ten

Three of those are worth a sentence more.

Air conditioning is a winter system. It dehumidifies as well as cools, which is why it clears a misted windscreen far faster than heat alone. Most cars engage the compressor automatically on the windscreen setting. If yours has stopped blowing cold in summer, it is also not demisting properly in winter — and the reason it stopped is often cheaper than a regas.

Wipers are a consumable and get treated as a fixture. A blade that smears in October is dangerous in December, when it is dark at four o’clock and the screen is covered in salt spray. They are among the cheapest parts on the car.

Do not scrape ice with the wipers. Lifting a blade frozen to the glass tears the rubber edge, and running the wipers against ice can strip the motor linkage. Clear the screen first.

Tyre pressure falls in the cold

Air contracts as it cools, so pressures drop with the season — roughly 1 psi for every 5 to 6°C the temperature falls. A car set correctly in August can be meaningfully underinflated by December without losing any air at all.

That matters more in winter than the number suggests. An underinflated tyre has a softer, less defined contact patch, which is worse at cutting through standing water and worse at braking on a cold, greasy surface.

Check them cold — before driving, or after the car has stood a few hours. A tyre checked after a run reads high because the air in it has warmed, and setting it to the placard figure when hot leaves it underinflated once it cools.

Winter tyres, all-season, or neither?

Honestly, for most Birmingham drivers: neither, and spend the money on making sure the tyres you have are legal and properly inflated instead.

The case for winter tyres is real. Their compound stays pliable below about 7°C where a summer compound hardens and loses grip, and the tread is cut to clear snow and water. In a country with reliable winters they are the obvious answer, and in much of Europe they are compulsory. **In the UK they are not legally required.**

The case against, specifically here: Birmingham gets a handful of genuinely icy mornings a year, main routes are gritted, and a set of winter tyres means buying five hundred pounds of rubber, storing four wheels somewhere, and paying to swap them twice a year. On a commute that is mostly gritted A-roads, the return is small.

All-season tyres are the sensible middle if you are replacing tyres anyway and you keep cars a long time. They give up a little dry braking against a summer tyre and a lot of snow performance against a winter one, and they need no storage and no swapping. If you are buying tyres in autumn, they are worth asking about.

What genuinely changes your winter grip more than any of this is having tread depth well above the legal minimum. Wet and cold performance falls away long before 1.6mm.

The Birmingham bit: it is the first 200 yards

The risk here is not the commute. Councils grit a priority network — the main routes, the hills, the bus corridors — and the A38, the Middleway and the arterial roads are usually treated before the morning peak.

Residential streets are usually not gritted at all. So for most drivers across the terraced inner suburbs and the estates, the dangerous part of a frosty morning is the first couple of hundred yards: an ungritted side street, parked cars both sides, a junction onto a treated main road, and cold tyres with no heat in them.

Two practical consequences. Cold tyres grip worse than warm ones for the first mile or two regardless of what they are, so the beginning of the journey deserves more caution than the middle. And a car that lives at the kerb rather than on a driveway is starting from a colder soak every morning — which is the same reason kerbside parking is hard on batteries.

What does it cost?

Most of the checks above cost nothing if you have them done alongside something already booked. If you are due a service anywhere near autumn, having it in September or October rather than January means the winter items get looked at before you need them rather than after.

When should you call a garage?

Book it in October, not December. That is the whole point of this page. A battery at 60% health will start the car all autumn and fail on the first properly cold morning, and there is no way to know that without a test.

Ask specifically for the antifreeze to be tested, because it is not part of an interim or full service. It is a two-minute job and nobody will do it unless asked.

Book sooner if the car is already cranking slowly, if stop-start has quietly stopped engaging, or if the heater is taking a long time to warm up — that last one can be a thermostat, which also means the engine is running cold all winter.

Tell us on the phone whether the car sleeps on a driveway or at the kerb and roughly what your daily journey is. Both change what is worth checking — a car doing four miles a day from a kerbside space needs different attention from one doing the M6 twice a week. Car servicing and winter checks in Birmingham, seven days a week, so a winter check does not have to cost you a day’s leave.