When the Cold Starts Biting

Cold mornings are hard enough without your car refusing to start. Engines, batteries, and fluids all feel the chill; especially if your car sits outside overnight. A few small habits can make the difference between a quick start and a morning of frustration (or a call to the breakdown service).

Here’s how to give your engine the best chance of coping when temperatures drop.

1. Keep the Battery in Good Shape

Flat batteries are the number one cause of winter breakdowns in the UK. Cold weather slows the chemical reaction inside the battery, meaning less power for turning the engine. If your starter motor sounds sluggish or your dashboard lights dim when you turn the key, your battery could be on its last legs.

Have it tested before winter sets in, especially if it’s more than three years old. Keep jumper cables or a portable booster in the boot just in case. And if you’re not driving much, consider a trickle charger; it keeps the battery topped up between trips.

2. Use the Right Engine Oil

Oil thickens in the cold, which can make it harder for your engine to turn over. Check your car’s handbook for the correct winter-grade oil; usually a thinner viscosity, such as 5W-30 or 0W-30. Using the right oil makes cold starts smoother and reduces wear on vital components.

While you’re at it, make sure you’re not overdue for an oil change. Old, sludgy oil struggles even more in low temperatures.

3. Top Up Antifreeze and Coolant

Your car’s coolant prevents the engine from freezing; but only if it’s mixed correctly. Most systems use a 50/50 blend of water and antifreeze, but always check your owner’s manual. If the antifreeze is too weak, the liquid can freeze and crack the radiator or engine block. That’s not a cheap fix.

Look for the recommended long-life coolant, and never top up with plain water unless it’s an emergency.

4. Don’t Ignore the Fuel Tank

Keeping at least a quarter tank of fuel helps prevent condensation forming inside the tank, which can lead to water contamination and rust. For diesels, it also reduces the risk of wax crystals forming in very low temperatures, which can block fuel filters. It’s a small precaution that keeps your fuel system happier through the frost.

5. Warm Up the Engine Properly

Modern engines don’t need long idling periods, but they do benefit from a gentle start. Fire up, wait a few seconds for oil pressure to stabilise, then drive smoothly. Don’t rev hard or floor the accelerator until the temperature gauge starts to move. Mechanical parts expand as they warm, and pushing them cold only adds unnecessary wear.

6. Keep Belts and Hoses in Check

Rubber components harden and crack in low temperatures. If you hear squealing belts or notice visible cracks, get them replaced before they fail. The same goes for coolant hoses; a small split in summer can become a burst pipe in winter. A quick visual check under the bonnet every few weeks can save a breakdown call-out later.

7. Check Your Glow Plugs (for Diesels)

Diesel engines rely on glow plugs to pre-heat the cylinders before starting. If your diesel struggles to fire on frosty mornings, one or more plugs may have failed. A simple test at a garage can confirm it, and replacements are usually inexpensive. Keeping them working properly means smoother starts and less smoke when cold.

8. Protect Against Moisture

Damp can creep into ignition components, especially on older cars. Keep the bonnet area clean and dry, and consider using a water-dispersing spray (like WD-40) on exposed electrical connectors. If your car is garaged, make sure the space is well-ventilated to stop condensation forming overnight.

9. Listen to Your Engine

Cold starts will always sound slightly rougher, but if you hear knocking, grinding, or extended cranking, something isn’t right. It could be a weak battery, a sticky starter motor, or thick oil. Don’t ignore it; the earlier you deal with small issues, the less likely you are to face a bigger one on the coldest day of the year.

Useful UK Resources

• AA – Winter Driving Tips
• RAC – Winter Car Maintenance Guide
• Halfords – Winter Maintenance Checklist