Grit, Salt and Soggy Sills: The Pre-Winter Check Most UK Drivers Skip

By the first week of November, plenty of UK councils have already sent a gritter or two out on test runs. You might not have seen the salt yet, but it is coming. And salt doesn't just make the car look scruffy — mixed with water and road dirt, it gets into seams, sits against metal and starts the slow business of corrosion. The good news? You don't need a ramp, a steam cleaner or a garage appointment to catch the worst of it. Twenty minutes with a torch, a hosepipe and a bit of common sense will do more than most drivers realise.

This is not a concours detailing routine. It is a salt audit: a quick, repeatable walkaround you can do before the 2026 gritting season properly bites, and again after a bad spell of weather. Here's the priority order we'd use at CarBay.

Start at the wheels — arches and liners first

Wheel arches are where winter does its quietest damage. Road grit gets blasted into the arch, sits behind the plastic liner and stays damp for days. Look for crunchy underseal, orange dust, flaking paint and trapped leaves. Clear out the leaves by hand — don't attack anything with a screwdriver — then rinse the arch with plain water. If the liner is loose or missing a clip, sort it. A liner that flaps about is just a salt scoop.

Sills and jacking points: the bits that fail MoTs

Run your eye along the sill, especially behind the front wheel and ahead of the rear wheel. Stone chips here are normal. Bubbling paint and soft underseal are not. Press gently with your thumb — not hard enough to dent anything — and note any crunching. Rust near a jacking point is structural, not cosmetic. If you can see flaking metal or a hole, stop poking and book it in. This is exactly the sort of thing an MoT tester will find later, usually at the least convenient moment.

Brake and fuel lines: look, don't poke

Get a torch under the rear of the car and look along the floor, around the rear axle and behind the fuel tank. Steel brake lines corrode quietly, and a line that looks grim under a layer of winter filth is worth a professional opinion. Don't wire-brush them, don't spray them with random potions and don't convince yourself that a bit of surface fuzz is fine. If the line is flaky, pitted or damp-looking, get it checked. Brake lines are not a wait-and-see item.

Paint chips and stone rash

Front bumper, bonnet leading edge, mirror caps and the lips of the wheel arches take the brunt. A tiny chip is an open door for salt. Clean the area, let it dry properly and use a touch-up pen if you have one. Don't seal over orange rust — that just hides the problem. If the chip has already started to bloom, treat it or get it treated. A £10 touch-up pen is cheaper than a bodyshop bill, but only if you use it before the salt gets comfortable.

Door seals, drains and wet carpets

Salt and grit don't just attack metal. They dry out door seals, clog drains and help water find its way inside. Wipe the seals clean, dry them and give them a light coat of silicone spray so they don't stick in freezing weather. Check the scuttle drain at the base of the windscreen and clear out leaves and muck. If the carpets are damp, don't ignore it. A wet carpet in November becomes a misted-up, smelly car by January, and the leak is usually easier to fix before it has had months to settle in.

Underbody rinse: simple, not savage

You don't need a pressure washer to shift winter salt. A watering can or a gentle hosepipe is often better, especially around seals, brake components and electrical connectors. Rinse the wheel arches, sills, subframe and the lower edges of the body. Avoid blasting directly into wheel bearings, electrical plugs or anything that looks like it would rather stay dry. Do it when the temperature is above freezing, and take the car for a short run afterwards so the brakes get a chance to dry off.

A sensible priority list

If you only have twenty minutes, do it in this order:

1. Brake lines and structural rust — anything flaky or holey goes to a garage.
2. Wheel arches and sills — clear debris, rinse, note any bubbling.
3. Paint chips — clean and touch up before the salt gets in.
4. Door seals and drains — clean, dry, silicone spray, clear the scuttle.
5. Underbody rinse — plain water, low pressure, no heroics.

The cheap kit that actually helps

A torch, a pair of gloves, an old towel, a watering can or hosepipe, a touch-up pen and a can of silicone spray will cover most of it. You don't need a salt-neutralising miracle product, a heated garage or a set of ramps. Plain water and a bit of effort do the heavy lifting. What you do need is consistency. A quick check now, then another after a really mucky spell, is worth more than one frantic clean in March when the damage is already done.

The point isn't to make your car immortal. It's to spot the difference between a bit of winter muck and the start of a welding bill. Twenty minutes now is a lot cheaper than a fail sheet later.