The first-freeze checklist

There is a specific week each autumn when the forecast first shows a number below freezing, and it is the most useful week of the year for this kind of work. Everything is easier to do while it is still mild, and everything is more annoying to do afterwards.

Nine things. Most of them are free and take minutes.

1. Change the washer fluid

Run the reservoir low, then fill it with winter-rated fluid and run the washers again to push it through the lines and jets. Topping up on top of summer fluid gives you a mixture with a freezing point you cannot predict.

Check the temperature rating printed on the jug. They vary a lot between products on the same shelf, and one rated to 20 F is not much use at 5 F.

2. Check the tires, properly

Two things: tread depth and pressure.

Tread depth is the largest single variable in how your car behaves in snow, and it costs nothing to look at. Pressure falls as temperature does — roughly one PSI for every 10 F drop — so the pressure that was right in September is low in November, and low pressure hurts both handling and fuel economy.

3. Get the battery tested

Free at most auto parts stores, a few minutes, and it is the single most useful diagnostic on this list. Cold reduces a battery’s available power while making the engine harder to turn, and a battery that is marginal in October fails in January.

Clean the terminals while the hood is open. Corrosion is resistance, and resistance is exactly what you do not want in the starting circuit on the coldest morning of the year.

4. Replace the wiper blades

If they are more than a year old, replace them. Rubber hardens with UV exposure whether or not you use it, and cold makes a marginal blade obviously bad. Most winter wiper complaints are age complaints.

If you are buying, a beam blade has no exposed frame for snow to pack into, which is the failure mode of conventional framed blades. The comparison is here.

5. Put the winter kit in the trunk

A blanket, a hat, real gloves, a pair of boots if you commute in shoes, and a phone cable that actually works in your car. Most of that is in your house right now, and the whole problem with it is that it is in your house rather than in the car.

Add a folding shovel if you do not have one, and charge the jump pack if you do. The full checklist is here.

6. Seal the garage, while it is still warm enough

A bottom seal can be fitted any time — it is a mechanical job, and cold only makes the material stiffer. A threshold seal cannot: it is adhesive-bonded to concrete and needs a clean, dry floor above the minimum application temperature in its instructions.

If your floor is uneven and a threshold is what you actually need, this week is the week. Working out which you need is here.

7. Do the paint and underbody, while you still can

Sealant needs a clean, dry surface and reasonable temperature, and every week you wait makes both harder to arrange. Twenty minutes with a spray sealant is the easy half.

The underbody coating is the half that matters and the half that needs ramps and an afternoon. If you are going to do it at all, this is the week. DIY versus a shop is here.

8. Clear the drain holes

Five minutes with a cable tie, and almost nobody does it.

Doors, rockers and sills have drain holes along their bottom edges, and they block with debris over the summer. A blocked drain hole turns a hollow cavity into a bath, which is precisely where winter rust starts. Poke each one clear and you will usually see water come out.

9. Fit the chains once, in the driveway

Only if you own chains, and only if you have never fitted them.

Twenty minutes on a dry afternoon tells you whether they fit your car rather than just your tire, whether you can reach the tensioners, and whether you can do it at all. The alternative is finding out in the dark on a road shoulder in a storm. More on that here.

What this week looks like

Three of the nine are free and take under twenty minutes between them. If you do nothing else this week, do the washer fluid, the battery test and the drain holes.