When winter rolls around and your windscreen is constantly frozen, you may wonder whether the sub-zero temperatures affect the fluids inside your vehicle. For example, does engine oil freeze? And what causes low oil pressure in cold weather?
Here, we’ll take a look at how cold weather affects your car lubricants, complete with some top tips to boost performance through the winter and protect your engine from freezing temperatures.
Does engine oil freeze?
Engine oil does not typically freeze, although it does become thicker (more viscous) in colder temperatures. It’s a bit like honey; when hot, it runs quickly, when cold, it is far more resistant to flow. The same can be said for some other vehicle fluids, such as gear oil.
Depending on your car, the oil you choose, and how cold it gets, this can have an impact on performance. Cold, slow-flowing engine oil has the potential to decrease proper lubrication during startup, leading to increased wear and strain on the engine. This is why you might experience low oil pressure in cold weather.
Meanwhile, a thicker-than-usual gear oil can make shifting transmission difficult and put undue stress on various components within the gearbox.
This is why it’s so important to choose fluids and lubricants that are appropriate for the climate you’ll be driving in. Different types have different viscosity levels, suited to various climates. You should always check your owner’s manual to find out what type of oil is best suited to your vehicle according to your driving conditions.
What is multi-viscosity oil?
Modern cars tend to be less affected by colder climates because they are compatible with multi-viscosity oils. A multi-viscosity (or multi-grade) oil performs in both hot and cold conditions. When it comes to motor oil with a W" (think winter), such as 5W-30, a lower number refers to a lower pour-point. The second number "30" is the operating viscosity of the oil based on the engine being warmed up.
These oils are specially formulated to perform differently depending on the outside temperature, protecting your vehicle from low oil pressure in cold weather.
Top tips for winter car care
While multi-grade oils are great for aiding proper lubrication in fluctuating temperatures, there are some additional things you can do to support your engine when the temperature drops.
Choose the correct oil weight
If your car is compatible with multi-grade oils, you will find a recommendation for the right type of oil for your needs in the owner’s manual, with a viscosity rating that looks something like 5W30 or 10W40.
Change oil before winter
If your oil is due a change, get ahead of the game by changing it before the colder weather sets in. Worn-out oil is often thickened with contaminants, while fresh oil flows more freely. This helps protect against low oil pressure in cold weather.
Avoid long periods of idling
It’s tempting to let the engine run while the heating gets going and the windscreen defrosts, but this is a bad idea. Ideally, you should de-ice your windscreen with the engine off first. Once safe to drive, let the engine run for just 30 seconds or so before setting off slowly. This reduces wear and tear on the engine while promoting healthy oil circulation in cold temperatures.
Avoid sudden acceleration and braking
You should avoid rapid acceleration, sudden stops and excessive braking, especially when you first start driving and the engine is still cold. These sudden movements put additional stress on the engine components while they are still warming up.
Avoid short trips
Very short drives don’t give your engine a chance to reach optimal operating temperature, leading to potential condensation in the engine oil. Where possible, take longer drives to allow the engine to warm up properly and burn off any accumulated moisture. For short journeys, consider walking or public transport instead.
Check essential fluids
As well as making sure you have fresh engine oil for the winter, you should also check other essential car fluids such as coolant, which contains antifreeze vital for protecting your engine in sub-zero temperatures.
Park under shelter
Where possible, park in a covered garage or sheltered spot. This can help maintain warmer engine temperatures between drives, reducing the load on lubricants during startup.
Nowadays, most cars benefit from high-performance, multi-grade oils and lubricants that are well-equipped to work efficiently in colder temperatures. Therefore, the most important thing you can do to protect your vehicle over winter is to choose, according to the recommendations in your vehicle handbook.