How to Warm up a Car Quickly in Cold Winter Weather
Drive off as soon as you can
An engine gets warmer much faster when it's being driven, and will take considerably longer to warm up when stationary.
The best thing to do is to get the car clear of snow and ice, and then as soon as it's safe, start driving. If possible, take a route which avoids sitting in traffic or at traffic-light junctions.
Consider an engine coolant pre-heater
Engine coolant pre-heaters are very common in countries where cold weather is a constant and I was first introduced to them by a friend who lives in Toronto, Canada. The basic principle is that a low current, low voltage device is added to the vehicle's coolant system and then plugged in to an external power source. The pre-heater gently heats the coolant system and keeps it at around 65°C as well as slowly circulating it.
The result of this is that an engine is already at an advantage of warm temperature and will get up to the optimum temperature must fast; meaning your vehicle's heater will start to produce warm air almost immediately.
I have an engine pre-heat in my car and I've noticed a huge difference in the speed that my car warms up. It's incredibly easy to fit (anyone with basic automotive repair knowledge can do it) and the device is very reliable. I plug mine into a smart plug so that I can turn the system on when I wake up and the car is ready to go when I leave the house.
Make sure the vehicle's thermostat isn't stuck
Most engines are fitted with a thermostat. When cold, the thermostat remains closed until the engine is up to optimum temperature. Once the engine is warm, the thermostat opens and allows the warm coolant to circulate the rest of the engine. If the thermostat is faulty, it may be opening too early or not at all.
If your car's cabin isn't getting warm over a long period of time you may need to get the thermostat checked out by a professional.
Consider an Oil Pan heater
Popular in the US, oil pan heaters attach to the metal oil pan (sump) on a vehicle and keep the oil warmer than it would otherwise be when cold.
This heater can be used for an engine block heater, transmission fluid heater, hydraulic fluid heater, fuel heater as well as thawing frozen pipes, water tanks etc.
Turn on electrical devices
Turning on electrical devices such as lights and heated windscreens will put the alternator under load and make the engine work a little bit harder. This light load will help the vehicle heat up faster.
Park in a Sunny Spot
Don't under estimate the power of the Sun, even in the coldest of weather. Even if your car is 2'c warmer parking in the sun it will warm up faster, so where possible avoid the shade.
Does your car have a pollen filter? Is it blocked?
Many modern cars are fitted with a pollen filter to prevent pollen entering the cabin in the spring and summer months. Whilst this filter is great for people with allergies it's easily blocked by dirt and other particulates.
When I first bought my second hand car the heater blower as almost useless, but as soon as I replaced the (black and gunky) pollen filter all the power came flooding back.
Are your cars heater controls working correctly?
Often overlooked but vital; is your car actually selecting hot air on the heater controls? May basic heater controls use a system on rods to select hot air on the system, and if those rods break if may appear that the heating is set to hot when it's actually stuck on cold.
Get a Remote Start system
Yes, it's true, you can now start your car remotely. Some manufactures on modern cars already provide this feature, but if your car is colder you'll need to source and aftermarket system.
The system is designed to start your car's engine remotely, whilst leaving the door locked. Some systems can also switch on the heater for you.
Check your Summer Coolant/Winter Antifreeze
The coolant in your vehicle is also an antifreeze, and if it's weak or very old it becomes less effective. A frozen engine is a very bad thing; expanding water can break vital engine components and even crack the engine block or cylinder head. It will also cause your engine to warm up much more slowly.
Make sure you've checked your antifreeze strength. I use the Draper Antifreeze checker which is cheap and effective.
Got a garage? Use it!
Place a thermostat in a garage and you'll quickly realise that it's a warmer place than outside, even in the depths of winter. If the garage is warmer so will your car be, so if you can, use it!
Warning: do not idle a vehicle in a garage. This causes an increase in poisonous gasses such as carbon monoxide and can kill.
Block the radiator vents in an older car
A car radiator does a great job of keeping the engine cool, but in cold weather it can cause the coolant to take a very long time to warm up.
Do this at your own risk and make sure you monitor it so that the engine never overheats: use a piece of sheet metal to block half of the airflow from cooling the vehicle. Keep it away from any hot or moving parts.
Oh, and did I mention, do this at your own risk!
Don't be tempted to over-rev a cold engine!
Revving a cold engine excessively isn't a very wise idea; it can put strain on components and cause excessive wear or cracks.