How Long Should You Idle to Stay Warm?
They say that idle hands are the devil’s workshop. Netflix might beg to differ on that. At any rate, a car’s idling engine has nothing to do with hellfire or questionable propaganda programming. It just runs until it’s out of gas.
Winter is coming. Again. Now is the time to get ready. There’s a little math in this episode, but we can make peace with the numbers, right? We are a people at peace in our automobiles. So, it follows that we could conceivably find ourselves stranded in our cars when severe winter weather hits. Unless the heater core is blocked or the fan is jammed, your car has heat. In most cars, this is a product of running the engine. That burns gas. And, the question presents itself: “How long can one run an engine for heat?”
Thanks to Justin Pritchard and AutoTRADER Canada, we have an answer. We have a formula based on three factors. By understanding three numbers, you can accurately determine how long you can run the car, for heat, based on how much gas is in the tank.
(All pics from video).
Down the Road
A car is a mobile shelter. Here, we find a lone vehicle on a remote road, as the sun goes down. It’s a pretty scene, but just how long could you expect to last, camped out in your car?
It’s all about those three numbers.
Running On Empty
Hint: if the needle is on the “E,” then the answer is zero minutes or hours.
Assuming you’re north of that low mark, then you can rest assured of heated time based on Justin’s handy calculations. It’s three numbers and two mathematical solutions. Please ready your expensive graphing calculators!
One. Engine Displacement
How big is it? In liters? You probably already know this. If not, then the number is probably printed in the owner’s manual, on the engine, inside the door or hood, or on the outside of the car somewhere. Look for 2.0T, 3.5, 5.7, etc.
Two. Fuel Capacity
How much gas does the tank hold? This too is found in the manual. You’ve read the manual, right? This is from Canada, so it’s also a metric number – in liters, not gallons.
Just remember it, zero-point-six.
Why? Because that is an approximate factor of how much gas, in liters, an engine burns up in an hour. This needs to be reduced based on the displacement, or size of your specific engine.
That’s the first calculation: 0.6 x XX liters = burn rate per engine hour.
Here, it’s 0.6 x 2.4 (l), rendering 1.4 liters (litres…) per hour as the rate of gasoline consumption.
NOTE: May not be accurate for diesel, hybrid, or of course, pesky electric vehicles.
NOW! Final Calculation!
Divide the total number of liters of gas in the tank by the consumption rate number. The product is the number of hours that you can idle the engine.
Okay, here’s a quick rundown, based on easy, rounded numbers:
Engine – 5.0 liters displacement;
Tank – 100 liters of ga (full);
0.6 x 5.0 = 3 liters of burn per hour;
100/3 = 33.33 hours of idle time.
Another note: if the tank is half full, or a quarter full, then adjust your middle number accordingly.
For a live recap, just,
Watch the Video:
AutoTRADER Canada / YouTube.
A short, seven-minute gem! That’s great information that you probably didn’t know. And, best of all, you don’t have a Subaru! No, no, best of all, you didn’t even need the calculator! For more automotive excellence, please visit,
It’s the biggest and best automotive channel based out of our neighbor to the north.
And, don’t forget www.autoTRADER.ca.