Idle or Switch Off my Car Engine?
When I first learnt to drive, I was told that it used more fuel to stop and re-start a car, than it did to leave it running, or idling. As I write this, I’m thinking that I obviously learnt to drive a long time ago!
It may have been true in the ‘dim and distant past’ but it certainly isn’t true nowadays with our modern cars. Starting a car’s engine uses only a negligible amount of fuel and doesn’t have a massive impact on the wear and tear of the engine.
Idling your car simply uses fuel and costs you money, while also spewing pollutants into the air.
I decided to find out what the cut-off point is now – in other words, at what point does it make sense to idle rather than switch off the car.
I was surprised by what I found out.
In a modern car, it’s 10 seconds.
Is that all?
OK, 10 seconds isn’t always practical – for example in traffic. So the rule of thumb is that if you’re going to stop somewhere for more than 10 seconds (except in traffic), it makes sense to switch off the engine. Use common sense to work out if it makes sense to switch off or to idle at these common idling spots:
- drive-through service lines,
- rail crossings,
- car wash queues,
- carpool lines,
- departure from concerts and sporting events,
- while talking to friends
- while using the cell phone.
By understanding the effects of idling and reducing the practice, you can improve your car’s performance, save money, and reduce pollution.
Is Idling Bad for Your Car?
Interestingly, excessive idling can actually damage your engine components. An idling engine is not operating at its peak temperature, which means that fuel does not undergo complete combustion. This leaves fuel residue that damages engine parts and can contaminate oil.
An idling car is the most inefficient car on the road — it gets zero miles per gallon
Warming Up a Car
What about warming up a car, especially in winter (unless you live in a hot climate)? Doesn’t the car need time to warm up before you can safely drive it?
Cars should be warmed up – but idling is not the way to do it, not even in cold weather!
The best way to warm up your car is to drive it. You need no more than 30 seconds of idling before driving away, even on the coldest days. Just avoid high speeds and rapid acceleration for the first 3 miles / 5km.
The catalytic converter – the device that reduces pollutants from the vehicle exhaust – doesn’t function properly when it’s cold, and the best way to warm it is to drive the car. You emit more pollution if the catalytic converter is cold.
The tyres, transmission, wheel bearings and other moving parts also need to be warm for the vehicle to perform well. Most of these parts do not warm up until the vehicle is driven.
Next: What about idling in diesel and hybrid cars? Also, which technology is available in Europe and Asia, but not in the US!
In the meantime though, here’s a thought:
An idling car is the most inefficient car on the road — it gets zero miles per gallon.
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Photo Credit: microsoft.com