Should You Leave Your Car’s Engine Idling? Myth Busted


rev up your engines, today I’m going to
answer the question, is it bad for your car to sit and idle for long periods of
time, over the years my customers and internet viewers have said. Scotty is it
bad for me to sit idling for long periods of time in my car, because some guys say
yes, some guys say no, what’s the truth well the truth depends on what type of
car you have and what kind of places you live in, let’s say you have an old beater
car, that’s so old it has a mechanical fan to cool the radiator
that runs off the water pump, and you live in a real hot area like Arizona, then
in that case, idling for extended periods of time isn’t a good idea,
your engine could easily overheat and it can be dumping a little bit extra
fueling in an old car and that will dilute your oil and your engine will wear out,
because there will be a lot of gasoline in your oil and that’s not a good thing, but
if you have a modern car that you take care of that has electric cooling fans,
they pull in tones of air, you don’t have to worry about the car overheating, so even
if you’re running your AC, those fans are sucking so much air through, you can sit
there idling, it’s not going to bother it even with the AC on, now of course
especially if your driving a gasoline car, you’re going to get bad gas mileage if it’s just
sitting there idling all the time, the car’s not going anywhere and it’s still burning up
gas, but for those of you with diesel engines, some of these diesel engines when
they’re just idling, they’re using mainly air and very little fuel, so with
a diesel idling you don’t really care that’s why you see a lot of these trucks,
they just leave them running all the time, but you’ll notice some modern cars
have this auto stop feature, when you come to a stop if you sit for any length of time, it shuts the engine off and then when you step on the gas it
automatically restarts the car, that’s to save gasoline and of course get better
gas mileage, but let’s say you’re waiting for a train and maybe you’re in the
Midwest and it’s one of those grain trains that goes for miles, you don’t want
to be sitting there idling for a really long time with your car and drive,
because with your car in drive, the transmission is being operated, the
torque converter is spinning and it’s got some drag on it, so if you’re going to
be sitting there idling for a while here’s a trick, either put it in park
or neutral, because then the transmission don’t be dragging on a torque converter,
and you won’t have a problem with the transmission which could overheat if you
leave it and drive sitting there for half an hour or more, I’ve seen people
who leave it in drive and let it idle for a really long time, and it can eventually
do damage to the transmission by overheating it, a transmission is not
made to be sitting with a drag on it with nothing running, it really needs to
be moving down the road, the air blowing through the radiator, cooling everything
down, and not just sitting there getting hot if you do have an older car with a lot
of mileage, like this Ceilca, it’s got 250,000 miles on it, if you’re idling for
a long period of time just sitting there and you start to smell something, quick
look under the car, and if you look under there and find that the catalytic converter
starting to glow red, you want to shut the car off right away, because as I said
before, if it’s an old car it might be putting a little bit too much gas into
it, running a little bit rich, and that can make the catalytic converter glow
red which is dangerous because it’s going to burn it out and it could even start a
fire when it gets that hot, but any modern well kept up fuel-injected car, the
computer makes it run so perfectly that you’re not going to get your catalytic
converter glowing red from idling for a long time, and let’s say you’re sitting
somewhere, here’s a trick I learned from the police, they’re sitting there for long
periods of time and here in Texas it’s hot so they want to be inside their car with
the a/c running, open your hood, give it a pop, and lift it up a little, with it lift
it up a little, the hot air will be able to escape better and make it run as
efficiently as possible, so now you know idling your car for extended periods of
time in any modern well kept up car isn’t really going to hurt anything, but of course
it’s going to be wasting fuel, I mean why leave it running if you don’t have to,
but just to be on the safe side, like I always am when I’m driving a car, keep
your eye on the temperature gauge, glance at it once in a while, because if
something goes wrong and the temperature gauge starts going towards the hot, shut
it off then, so if you never want to miss another one
of my new car repair videos, remember to ring that Bell!