Is it bad to idle for long periods?

[Pope]

During long idle periods the oil gets hot, but not hot enough to help boil away any condensation/water that may accumulate. This is why short hops in the city are more detrimental to engine longevity than highway driving. Idling allows carbon buildup to happen. Below 800 deg F, carbon will not burn off. Semi trucks may idle for long periods but they also get on the highway and help burn off the condensation and carbon.

Sponsored

 

[aighead]

I take a lunch nap pretty much every work day, in my car. I've been wondering about this as well. I'm on the side of not worrying too much about it. I will suggest paying attention to where you park though, regarding carbon monoxide poisoning... Remember backing into a snow pile or pile of leaves or something may not allow for as much exhausting to happen as needed. I know those things melt or blow away a lot but sometimes they may not...

 

[civicls]

I idled for 2 hours one time while I was stranded on the highway because of a truck fire. I needed the AC.

Nothing happened except my gas decreased a bit.

Yea bro I drove a Ferrari 458 Italia, a Centenario, a 918 Spyder, and a Gallardo as a daily driver. But it was too small with little legroomso I opted for a Civic sedan. Much better legroom.

 

[civicls]

What did you do, file bankruptcy and got a Civic after all those Supercars?

Precisely.

 

[Gruber]

Just listen to this guy, and this thread can just as well be closed. He is of advanced age, (or just old, if you prefer), but he is fully aware how modern cars are different from ancient cars, so some old tales don't apply any longer, while some things stay remarkably the same. In contrast to many people out there, who just remember what their father told them. It usually still applies, but just not always.

Cooling and lubrication are much better with engines like this civic. There is no worry that a well-designed contemporary car engine should be poorly lubricated while idling, or that it should overheat.

Interesting point is that both old carbureted cars of yesteryear and todays' cars with GDI might pick up excess gasoline in the oil while idling. The difference is that the dilution in DI depends on how often you idle a not-quite-hot engine (winter), while with carburetors it's more how long you idle, because the mixture may be richer all the time, even with hot engine.

Btw, a good way to reduce the carbon build up on the intake valves because of idling is to have some gasoline in the oil because of idling.....

 

[civicls]

Engineering Explained is also has a nice way of explaining from a physics perspective.

 

[MrBrig]

Most important is ;

..... if your car is idle and the air conditioner is on, you risk carbon monoxide poisoning.

This doesn't sound right to me. This would mean that when stuck in traffic or at a stop light people would be breathing carbon monoxide.

 

[Captaindicki]

When in doubt, just ask Scotty

 

[REBELXSi]

This doesn't sound right to me. This would mean that when stuck in traffic or at a stop light people would be breathing carbon monoxide.

We are... just not enough to kill you instantly.

 

[civicls]

This doesn't sound right to me. This would mean that when stuck in traffic or at a stop light people would be breathing carbon monoxide.

sometimes, you just gotta believe...

 

[Snoopyslr]

This thread is almost more ludicrous than the oil threads. Some great laughs in here.

Idling your car is not going to kill it or you

 

[late camaro]

This thread is almost more ludicrous than the oil threads. Some great laughs in here.

Idling your car is not going to kill it or you

If it is a concern, lag bolt a carbon monoxide detector to your dash, and actually know if there is an issue, Safety first!

 

[civicls]

True. I know it is a real concern for folks running off an icy road in the snow and the exhaust not dissapating because the snow will melt somewhat under the car, but the exhaust is held under the car somewhat.

Normal conditions though? I don't think it's a problem. Again, with the aforemented cops sitting for hours idling. I've sat in trucks for hours freeze protecting crops, engine idling all night to run the heat. If there's nothing causing the exhaust gasses to accumulate, they don't collect and really pose a significant risk. I'm sure there may be an example here and there but most would be because of some other environmental aspect causing the confinement of exhaust gasses

I don't see how you guys think co2 is entering the cab. The exhaust is in the back or th car, and fresh air is vented right beneath wiper stocks. Even if you were sitting in a traffic jam, there still is fluctuating air pressures and air is still vented above the hood...

Ps...not you but "other" users

 

[Turboroe]

I think alternators run a 3:1 pulley and don't make their rated amperage until something like 6k RPM, or 2k engine. Not all are the same but they generally follow something similar. I had read about years ago when looking at using idling cars and inverters for backup power in lieu of a generator since I figured you've got a huge has tank on a car and you know it oughta run vs a generator that could be laid up for months. In the end, it does work for a little power here and there... but it's no replacement for a generator. To get the ~1 kw the alternator could provide, you'd need to have the car's idle set 3x higher than stock and you're getting less evergy than the smallest generator. It should make plenty to hold the battery at idle. It might be more questionable at night running lights and such... but I've not heard of police cars dying as their batteries drain overnight from idling and the alternator not covering the electrical needs. I've definitely driven a car at night with a bad alternator and *just* made it home (lights were on... adding to the drain). By the time I got home, lights were very dim and I was having misfires.
...
I

OK, Just to clear things up, batteries don't care about amps, they care about voltage, and the voltage then drives the amps that the battery needs (and not a single amp more), no matter how many amps your alternator can generate.

So if your car battery with engine off is, say 12.4V, then anything above 12.4V applied to the battery will be charging it.
So to check if it is charging at idle, just measure the voltage with engine off and then with engine on. If voltage is the same or lower with engine on, then you have a bad alternator.

OK so, we are talking about a 2019 civic not a 1980 WV beetle, and Alternators have advanced a long way in the past decades. On our civics and most any car produced over the last 15 years, even at idle the alternator is producing some good 14~15V, so there is absolutely no problem in idling as far as the battery is concerned.
In fact, it is actually beneficial for the battery because applying voltages above 13.8V prolongs battery lifespan by reducing cell sulfation.

 

[charleswrivers]

OK, Just to clear things up, batteries don't care about amps, they care about voltage, and the voltage then drives the amps that the battery needs (and not a single amp more), no matter how many amps your alternator can generate.

So if your car battery with engine off is, say 12.4V, then anything above 12.4V applied to the battery will be charging it.
So to check if it is charging at idle, just measure the voltage with engine off and then with engine on. If voltage is the same or lower with engine on, then you have a bad alternator.

OK so, we are talking about a 2019 civic not a 1980 WV beetle, and Alternators have advanced a long way in the past decades. On our civics and most any car produced over the last 15 years, even at idle the alternator is producing some good 14~15V, so there is absolutely no problem in idling as far as the battery is concerned.
In fact, it is actually beneficial for the battery because applying voltages above 13.8V prolongs battery lifespan by reducing cell sulfation.

Mostly right... but you cannot assume an alternator on a car at idle is producing rated output. Amps absolutely matter because you can't have power without both voltage and current. You need a conductor, a magnetic field and relative between the two to generate a voltage. You can generate more voltage by affecting either the strength of the field or by changing the rate the winding are being cut by the magnetic field. The alternator has a voltage regulator to hold voltage constant, within the capabilities of how much field it can provide. Once you reach that limitation, all you can do is speed it up, as it should limit field current to prevent damage. If you have a car sitting at idle, it will certainly maintain ~14 volts. If you think you're getting the rated capacity and have ~1kw of available power from idle... you'd be wrong. Eventually, voltage will droop because you'll max out the field on the alternator... and the battery will be discharging, even with the car running.

Without any high draw items added though (i.e. sound system), the alternator should be sized to serve all loads without discharging the battery.

While alternators have been sized larger for a long time, I'm pretty sure they've been brushless 3 phase AC generators with a rectified output for a long time... decades. That way you don't have to replace brushes.

Sponsored