As temperatures begin to fall lower every night and you start walking out to a nice layer of frost on your windshield, you might be thinking more and more about going out a bit earlier to give your car some time to warm up. People often go back and forth about whether that’s a good idea or not, and likely will until the end of time. Luckily for you, we’re going to put this to bed right here, right now.
Before getting into this, it’s important to get some definitions out of the way. First, warming up a car means something different to everyone. It could mean the oil has fully circulated the system and lubricated the engine, it could mean the metal components of the engine have reached operating temperatures and fully expanded, or it could mean the cooling system has reached operating temperature and the heater is pushing hot air into the cabin.
For the health of your engine, only the first of those is necessary. After just 20 to 30 seconds of idling, your engine will be fully lubricated and ready to safely drive wherever you need to go. You must still drive gently at least until the coolant is at operating temperature, but an engine does not benefit from any extra idling time once the engine is lubricated.
Leaving the engine running for extended periods of time only wastes your hard-earned fuel and creates unnecessary emissions.
That being said, some of us choose to let our car run for 10 or 15 minutes in the morning, not for the health of the engine, but for our own salvation. There are few feelings worse than getting into a freezing cold car covered in ice at -25°C, knowing it’s going to be several minutes before you get even the tiniest bit of warmth from the vents. Letting the engine run for a few minutes, albeit unnecessary, allows the cooling system to reach its operating temperature, which is what provides heat to the interior heater. Coming out to a nice warm vehicle is a far better alternative to shivering and freezing your whole commute, but is it bad for your vehicle?
The short answer is no. Letting your car warm up a few extra minutes some mornings is not going to have a profound effect on the life of your engine. Some people make points about condensation developing within the crankcase or gasoline diluting the oil due to the rich air-fuel mixture created by idling. These points are somewhat extreme and may come into effect only after hours of idling day-in and day-out over a long period of time, but generally speaking, if you want to warm up your car for 5 or 10 minutes to get yourself through a cold snap, your car will be just fine.