Hello everyone, I am wondering if there is any reason why letting a car engine idle for extended periods of time would inherently be bad for it. I know that whenever the engine is running everything is inherently wearing out and with all else being equal the more hours on it the more frequently it will require maintenance, but is there anything worse about idling all day than, say, driving down the highway all day? For the purpose of this question let's assume that the vehicle in question has a well maintained and correctly functioning modern fuel injected engine, a good cooling system that keeps the engine's temp in a normal range at all times, and no significant design flaws.
Anything inherently bad about idling?
- Thread starter Avery4
- Start date
Originally Posted by CT8
Why are you wondering?
I am mostly wondering out of curiosity. I have heard arguments that idling is bad/worse on the engine than driving normally for various reasons and I am wondering if there is any truth to this. I don't idle much. My rule of thumb is if I am going to be stopped for less than 5 minutes I leave it running, anything more than that I shut it off.
Why are you wondering?
I am mostly wondering out of curiosity. I have heard arguments that idling is bad/worse on the engine than driving normally for various reasons and I am wondering if there is any truth to this. I don't idle much. My rule of thumb is if I am going to be stopped for less than 5 minutes I leave it running, anything more than that I shut it off.
Police cars, taxis and road construction supervisors pickups spend a great deal of time at idle with the climate control on.
Wear? Yes. Particular issues? I never heard of any.
Wear? Yes. Particular issues? I never heard of any.
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
Not so much of an issue with roller cams today.
Originally Posted by Chris142
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
Originally Posted by Avery4
Originally Posted by Chris142
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
I do believe that spinning parts are lubricated better at higher speeds.
Originally Posted by Chris142
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
I do believe that spinning parts are lubricated better at higher speeds.
Originally Posted by Chris142
Originally Posted by Avery4
Originally Posted by Chris142
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
I do believe that spinning parts are lubricated better at higher speeds.
That is likely the case, but the load on the spinning parts is also higher at higher speeds so the parts would need more lubrication than when under a very low load idling.
Originally Posted by Avery4
Originally Posted by Chris142
On older stuff like cam in block v8's idling was bad. The cam got oiled from oil thrown off the connecting rods. Idling your 327,396,340,383,440,400,455,302,351,429 etc would result in a flat cam.
Not so much of an issue with roller cams today.
I didn't know that, thanks for sharing! Perhaps that is where the myth that idling is bad because the oil pump doesn't produce much pressure/flow at idle came from
I do believe that spinning parts are lubricated better at higher speeds.
That is likely the case, but the load on the spinning parts is also higher at higher speeds so the parts would need more lubrication than when under a very low load idling.
Yea, I wouldn't be worried about the engine, but the accessories. The alternator in particular. At idle it is only putting out a fraction of its output, but is generating a lot of heat it can't get rid of since the engine compartment is hot and there's low airflow. Not saying I'm worried about them bursting into flames, but I'd be willing to bet it shortens the life of them. Also things like cable looms, wire jackets, and other plastics will fare worse over time.
Granted, this is all splitting hairs, the car is mostly designed for these things, just might take a little bit off the end of life of some components.
Granted, this is all splitting hairs, the car is mostly designed for these things, just might take a little bit off the end of life of some components.
NO! Not in today's computer controlled engines. Engines with slob carburetors of yesterday, maybe. And even then, we'd just need to do more frequent maintenance.
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It's a fuel waster.
My father in law does this occasionally with his 2000 Ford F-150 with 4.2L 6 and 250k+ for up to 10 housr periods during power outages at his coastal home.
He hooks up a 3000W invertor directly to battery of his idling truck and it powers his home in terms of gas boiler heat/hot water, fridge, lamp, TV and fan. He guesses it burns 0.5 gallon per hour doing this.
He has been doing this for last 10 years and no ill effects.
He hooks up a 3000W invertor directly to battery of his idling truck and it powers his home in terms of gas boiler heat/hot water, fridge, lamp, TV and fan. He guesses it burns 0.5 gallon per hour doing this.
He has been doing this for last 10 years and no ill effects.
Originally Posted by BMWTurboDzl
It's a fuel waster.
Ya.....but. Since most food places here are still to go we have been getting food then going to a park and eating in the car under a tree. It was 101F saturday so we kept the AC on
It's a fuel waster.
Ya.....but. Since most food places here are still to go we have been getting food then going to a park and eating in the car under a tree. It was 101F saturday so we kept the AC on
Diesel ambulances idle 24x7 so I am told. Maybe only in the winter. They get some odd problems.
Originally Posted by ctechbob
Yea, I wouldn't be worried about the engine, but the accessories. The alternator in particular. At idle it is only putting out a fraction of its output, but is generating a lot of heat it can't get rid of since the engine compartment is hot and there's low airflow. Not saying I'm worried about them bursting into flames, but I'd be willing to bet it shortens the life of them. Also things like cable looms, wire jackets, and other plastics will fare worse over time.
Granted, this is all splitting hairs, the car is mostly designed for these things, just might take a little bit off the end of life of some components.
I've read that GM goes out to the desert on a hot day, and parks the car in front of a brick wall with every accessory on, and lets it idle for the day.
But every part is brand new so...
Everything wears out. Idle used to be hard on vehicles, now I think it's kinda in the noise.
Yea, I wouldn't be worried about the engine, but the accessories. The alternator in particular. At idle it is only putting out a fraction of its output, but is generating a lot of heat it can't get rid of since the engine compartment is hot and there's low airflow. Not saying I'm worried about them bursting into flames, but I'd be willing to bet it shortens the life of them. Also things like cable looms, wire jackets, and other plastics will fare worse over time.
Granted, this is all splitting hairs, the car is mostly designed for these things, just might take a little bit off the end of life of some components.
I've read that GM goes out to the desert on a hot day, and parks the car in front of a brick wall with every accessory on, and lets it idle for the day.
But every part is brand new so...
Everything wears out. Idle used to be hard on vehicles, now I think it's kinda in the noise.
Originally Posted by BMWTurboDzl
It's a fuel waster.
That is why auto start/stop exists to BITOG dismay.
It's a fuel waster.
That is why auto start/stop exists to BITOG dismay.
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