Leaving The Engine Idling

[cooked]

I would be interested in knowing how long engines can safely idle. Unfortunately for various reasons I must remain in my Vigo for considerable periods while my wife conducts official business so sometimes I must stay for an hour. Currently I tend to run the aircon for a few minutes every 10 to keep the cab tolerable. I wiuld rather run it longer if I could know it is safe.

An hour?! Bloody 'ell. You need a camper van mate.

Medical reasons mate ...not choice.

urban myth. Well maintained A/C in cars are relatively harmless (better than dying of heat stroke).

[Lickey]

Harry, it wont hurt the engine atall, tick-over as long as you want, on start up, just rev it a little, make sure the alternator has kicked in, unless of course its done 400k and only one oil change, the valve guides will be worn out and carbon will build up quickly on valves, piston ring wear ect ect,,,,

And even with a water cooled turbo, its still recomended to allow a cool down period after a hard run/pull,

Cold weather starting? no problem, with all the fuel additives, water jacket and fuel heaters,

[cocoy]

wouldnt it be considered idling when your are stuck in traffic.. for more than 30 minutes? in some cases more than an hour.

[nullx8]

I would be interested in knowing how long engines can safely idle.

if you do not accelerate = forever !

[nullx8]

quite amazing how the rules of physics seem to change in Thailand

anyway for the rest of the Galaxy:

there are only 2 Situations where a normal Otto-Engine gets into trouble.

1. if you pull a trailer with almost the same wight of the car

2. idle

unless you are a rowdy or transport raverocks (this does not include mothers in law) you can ignore the first one.

for the idle, Cars are designed to be cooled down somewhat by 2 ways.

the intercooling system (water) and the Air flowing trough the car while driving.

in order to have the water cooling working the car needs to move in order to cool down the water heated up by the engine.

this is not always the case (traffic and idle) so since about 60 Years or so most cars come with a electrical or mechanical Fan installed in front or behind the radiator. this magically device simply "fakes" the Airflow if you do not move.

so if you start the engine and not move, this fan will provide the coooling airflow for you, if you drive the fan will not run at all.

in a modern car you may notice this if you rapidly stop somewhere with a open window, you may hear then the fan start (if it is electrical)

or if you cold start the car, just few secounds later the cooling fan will start as well. (this is not old design, its simply required and life preserving for the engine itself)

so long storry short: the engine is designed to simply run forever in idle !

BUT, in slow traffic or on extremly heavy load, the situation changes.

and cars like the Toyota Altis are simply not designed to stay forever in jams,

this is why the taxi's have some times lifted up the hood a few centmeters to provide additional airflow.

you wont see that in a Taxi in germany or in a taxi in hongkong, because a Mercedes Benz or a Toyota Crown IS Designed for this scenarios.

so in short (again): the worst thing you can do to your engine (in theory) is to stuck in traffic (stop and go)

because you need alot more power to get it all the time moving again, but you not provide the required airflow to cool it down, in stop and go.

but this is the 20th century, so most vehicle are designed to stand that.

about the Yoyota's user manual i read before, well i guess it was written by the Thai engeneers, but the cars where designed in Japan, which is another Galaxy where normal rules of physics do apply ... so thats total non-sense !

if the engine is Turbocharged (Not supercharged) and its running in extreme heavy load the Turbocharger will be easy overheated,

but again, its designed for that to happen, the engine does pump engine oil with high pressure at all times trough the bearings (even in idle) to ensure its function.

the case materials are mostly not more then one piece to avoid bending holes.

lets assume you really are in the gravestone business or have your home on a trailer.

driving up to Ang Khang or so always full acceleration but very low speed (because you got a 2,5L Isuzu diesel instead of a 3 Liter d4d Turbocharged engine)

... the Turbocharger will glow like your flashlight from the heat.

because of the high amount of Diesel burned the outtake carries more burned fuel, and the heat builds up.

then you decide to stop at a gas station, you slowing down your Road Train, Turnlight, merging, and finally reach the Pump.

this 30 secounds are already enough "idle" to cool down the critical parts and let them back apear just as normal.

so for the save side (after a marathon like this) .. you may let it running for a minute or so

but not to cool it down, more to make sure it does not cool down too fast.

for all other scenarios (specially in flat thailand) this is just nonsense costs gasoline but keeps the interior cool (and this is sure the main reason for ideling engines arround here)

about opening the hood in the night or so, i guess its clear now that this is just false education and group pressure to do it

the neighbor does it .. so do i ..

the only benefit you get is that if someone want to steal your battery, they not have to smash the window of the car.

or if the car is stolen, its more easy to disconnect the battery to make sure the alarm not goes off

[VocalNeal]

you may let it running for a minute or so

but not to cool it down, more to make sure it does not cool down too fast.

All well and good (mostly) until it got to this glaring error. Engines usually heat up slightly when shut off. I believe the correct expression is heat soak.

Edited November 14, 2012 by VocalNeal

[bdw]

I lock them if the driver isn't watching !

[beethoven]

I never leave my car idling if there are no passengers in the car, it would be stolen before I got back. If there are passengers I would leave the car idling to keep the A/C on.

I never lift the hood but have seen taxi drivers tend to do it a lot. I think they lift the hood to cool the engine and also extend the life of the rubber hoses and other parts of the car engine. I don't think there is any benefit in cooling the engine block itself.

[rixalex]

I never lift the hood but have seen taxi drivers tend to do it a lot. I think they lift the hood to cool the engine and also extend the life of the rubber hoses and other parts of the car engine. I don't think there is any benefit in cooling the engine block itself.

Surely it goes a bit further than there being no benefit in cooling the engine block itself. Surely it is of a detriment to cool the engine block. Engine block runs most efficiently when they are hot. Cooling them down so as to help save rubber hoses and other auxiliary components seems a bit daft.

Exception of course is if the car has a problem with over-heating. But as i say, in my neighbourhood the people that do this hood raising thing aren't the people running ten year old ragged taxis, they are people with brand new cars who don't travel very far. Seems silly to me.

[transam]

I never lift the hood but have seen taxi drivers tend to do it a lot. I think they lift the hood to cool the engine and also extend the life of the rubber hoses and other parts of the car engine. I don't think there is any benefit in cooling the engine block itself.

Surely it goes a bit further than there being no benefit in cooling the engine block itself. Surely it is of a detriment to cool the engine block. Engine block runs most efficiently when they are hot. Cooling them down so as to help save rubber hoses and other auxiliary components seems a bit daft.

Exception of course is if the car has a problem with over-heating. But as i say, in my neighbourhood the people that do this hood raising thing aren't the people running ten year old ragged taxis, they are people with brand new cars who don't travel very far. Seems silly to me.

I do it when home as ''perhaps'' a battery longevity exercise.

[Neilly]

Currently I tend to run the aircon for a few minutes every 10 to keep the cab tolerable. I wiuld rather run it longer if I could know it is safe.

As other peeps have said, it's no problem...we leave ours running all day sometimes, and in summer it's over 50 deg C here...no harm done in the last seven years we've been using Hilux's

[funcat]

The other day,while waiting for my daughter to finish horse riding practice,I've noticed a car drives in and parks next to mine...the driver comes out smokes a cigarette and the lady stays in the car while smoking,but leaves the door wide open...the car idles and AC is on(could hear it clicking on and off)...the lady stays in the car for an hour with the engine running!!...need to add,that it was quite a cool afternoon in CM that day,no need for AC at all...the car didn't blew up,so I guess it's OK to idle as long as you like

[nullx8]

you may let it running for a minute or so

but not to cool it down, more to make sure it does not cool down too fast.

All well and good (mostly) until it got to this glaring error. Engines usually heat up slightly when shut off. I believe the correct exp<b></b>ression is heat soak.

That is absolutly correct. But ignored, since there is alot of confusion going on already.

Heatsoak happens only if the engine does still running, simply heating up the intake air too much,

In modern cars this is not abig problem since the engine does know the intake temperature, but on a older car this can be overkilling.

However heatsoak is a common "problem" on high performance torbocharged gasoline engines.

But not really on a common pickup truck or even a personal vehicle.

Additional the cool down too fast i had refered to supposed to give some understanding about the things actually happens in aengine. (Its not exactly like in a water kettle)

Btw. if you heat up the engine because of heavy load, turn the key, the "heat soak" will happen for sure, but its harmless because the engine is shut off.

Most turbocharged engines have additional electrical fans, keep running for a few secounds after you turn the key, for this to prevent.

Not exactly the soak itself, more to establish a better start envioment if you start again right after.

[VocalNeal]

Again more nonsense which as you say "is ignored"

[pbeieio]

I got a copy (in english) of a users manual for my turbo diesel Vigo, one year after I bought the car from Toyota. It recommends that you leave the engine idling for 5 mins after "sudden stopping after high speed". This avoids cooking the turbo!!!! Thanks for the advice, (one year late), Oh WHAT a feeling!!!!

[Spoonman]

To be fair your Thai language owners manual probably tells the same story.

[Lickey]

There is a lot of difference between a fast run and a hard pull for a turbo, in easy terms, when a vehicle reachs the speed you want, the turbo just spins, does nothing, same if the vehicle is loaded, once it reaches speed, turbo does nothing, but in both repspects, it helps get to your speed more quickly,

EG, i used to drive an 8wheel 340 Scania tipper on a road planing job, perhaps 1.5 hrs flat out drive to the job, perhaps some time waiting to load, at this stge i would put a potato wrapped in foil on the exhaust pipe where it went into the silencer, so now with the hard pull home at 32.5 tons, it would be nicely cooked, there was no way it would cook when truck was empty, barely warm,

What im saying is the fast run cool down period is not so important as the hard pull period, just longer to allow cooler oil and exhaust gases to cool the turbo, most pick-ups are designed to take loads up to 1.5 tons, if its not doing that the turbo is having a real easy life..

[bobo42]

Heatsoak happens only if the engine does still running, simply heating up the intake air too much,

In modern cars this is not abig problem since the engine does know the intake temperature, but on a older car this can be overkilling.

However heatsoak is a common "problem" on high performance torbocharged gasoline engines.

But not really on a common pickup truck or even a personal vehicle.

Additional the cool down too fast i had refered to supposed to give some understanding about the things actually happens in aengine. (Its not exactly like in a water kettle)

Btw. if you heat up the engine because of heavy load, turn the key, the "heat soak" will happen for sure, but its harmless because the engine is shut off.

Most turbocharged engines have additional electrical fans, keep running for a few secounds after you turn the key, for this to prevent.

Not exactly the soak itself, more to establish a better start envioment if you start again right after.

Actually, the term "heat soak" is not very well defined. The term can be applied to at least of couple of different conditions that are not related.

"Heat soak" (as I typically think of it) refers to the time period immediately after a car's engine is shut off. It is characterized by the fact that the engine's waste heat is no longer being carried away by the moving coolant fluid. This will cause some engine components, and the cooling fluid itself, to become hotter than they would typically be when the engine is operating normally. By this definition, all cars experience a period of heat soak each and every time they are stopped from normal operating temperature. This is something that is considered in the design of engines and cooling systems, and tolerances and operating guidelines are set appropriately with this in-mind. It is not a "problem" per se, but simply a state that is part of the normal cycle of operation, hence engines should be designed and operated with this state in-mind.

The "heat soak" that you are referring to, is often used to characterize the overheating of intake air - usually of a turbocharged engine, but can also be applied to similar conditions of normally aspirated engines. This usually refers to a "problem" or sub-optimal condition, rather than a normal state. I agree that intake temperature sensors would greatly mitigate some detrimental effects of this condition.

I believe that some other posts in this thread are referring to "heat soak" per the first definition I have written in this post. Given that, it would not be surprising to me if some cars recommend a short period of slow to normal operation before shutting down - to allow the coolant fluid to carry away any excessive heat that may have been built up in the engine.

Of course, I would always defer to the operating instructions, as these are (mostly) put forth by the designing engineers, who (mostly) are working in the interests of engine performance and longevity.

[Spoonman]

most pick-ups are designed to take loads up to 1.5 tons

Where did you hear that ?

[transam]

most pick-ups are designed to take loads up to 1.5 tons

Where did you hear that ?

Mine is one ton, BUT the natives load till the bumper will not scrape the black top.

[Lickey]

most pick-ups are designed to take loads up to 1.5 tons

Where did you hear that ?

I dont hear anything anywhere, a design weight is always above the recommended weight,

[mogandave]

I would be interested in knowing how long engines can safely idle. Unfortunately for various reasons I must remain in my Vigo for considerable periods while my wife conducts official business so sometimes I must stay for an hour. Currently I tend to run the aircon for a few minutes every 10 to keep the cab tolerable. I wiuld rather run it longer if I could know it is safe.

An hour?! Bloody 'ell. You need a camper van mate.

Medical reasons mate ...not choice.

Harry:

We use Vigo's and other diesel pickups for our work trucks, they sit on a pipeline ROW and idle 12 hours a day. The truck motor is used to supply electrical power to the computer equipment mounted inside the vehicle and the AC has to run all day, also for the computers and operator comfort. Doesn't hurt the motor at all. Does help to change the oil once a week and when they do hit the highway they smoke like crazy for the first 10 minutes or so. The AC won't work as efficently when sitting so we even mount fans in the front of the truck to provide airflow through the radiator.

We've been doing this with these type of trucks and other makes for many years with never an engine failure from idleing. These little diesels in the pickups here are tried and tested and basically bulletproof.

I don’t think the engine is idling if it is generating electricity and running the AC. It is my understanding “idling” refers to an engine that operating without load, that is to say when the engine is idle.

[cowslip]

Engines are left running to keep the air going and the cab cool.

Diesels especially produce a lot of power on "tick-over" it is quite wasteful to leave the engine running

Leaving any engine on "idle" driving the air is even more so.

A standing vehicle relies entirely on the fan to cool the engine so this is just another load on the standing vehicle.

I would say that the average driver in Thailand hasn't got a clue what is or isn't an economical driving practice and just listens to myths and legends promulgated by their peers.

in fact idling for any length of time is a pretty good way to overheat, overload and generally fuc_k up your engine

Oil companies make all sorts of claims about damage to engines on start-up - it helps sell oil - the logic is that the surfaces have less lubrication after standing for some time and the cool oil is circulated less quickly - but how much this really affects the engine? well i wouldn't trust an oil company to give a straight answer - they can't even tell you how much they've spilt without massaging the figures.

Edited November 18, 2012 by cowslip

[transam]

Engines are left running to keep the air going and the cab cool.

Diesels especially produce a lot of power on "tick-over" it is quite wasteful to leave the engine running

Leaving any engine on "idle" driving the air is even more so.

A standing vehicle relies entirely on the fan to cool the engine so this is just another load on the standing vehicle.

I would say that the average driver in Thailand hasn't got a clue what is or isn't an economical driving practice and just listens to myths and legends promulgated by their peers.

in fact idling for any length of time is a pretty good way to overheat, overload and generally fuc_k up your engine

Oil companies make all sorts of claims about damage to engines on start-up - it helps sell oil - the logic is that the surfaces have less lubrication after standing for some time and the cool oil is circulated less quickly - but how much this really affects the engine? well i wouldn't trust an oil company to give a straight answer - they can't even tell you how much they've spilt without massaging the figures.

Think l must disagree.

[Spoonman]

Engines are left running to keep the air going and the cab cool.

Correct.

Diesels especially produce a lot of power on "tick-over" it is quite wasteful to leave the engine running

Leaving any engine on "idle" driving the air is even more so.

Why is it wasteful ?

A standing vehicle relies entirely on the fan to cool the engine so this is just another load on the standing vehicle.

I would say that the average driver in Thailand hasn't got a clue what is or isn't an economical driving practice and just listens to myths and legends promulgated by their peers.

in fact idling for any length of time is a pretty good way to overheat, overload and generally fuc_k up your engine

A non modified vehicle should be able to cool itself whether a WOT or Idle, if it does not then the manufacturer has got it wrong, how many times have you heard of a recall due to over heating at idle ?

Oil companies make all sorts of claims about damage to engines on start-up - it helps sell oil - the logic is that the surfaces have less lubrication after standing for some time and the cool oil is circulated less quickly - but how much this really affects the engine? well i wouldn't trust an oil company to give a straight answer - they can't even tell you how much they've spilt without massaging the figures.

Vehicle manufacturer also understand the concept of a cold start. why do taxi's that rarely turn the engine off get hundreds of thousand of KM's from an engine, because they are never allowed to cool down.

[Lickey]

Vehicle manufacturer also understand the concept of a cold start. why do taxi's that rarely turn the engine off get hundreds of thousand of KM's from an engine, because they are never allowed to cool down.

Cant agree with you on this one, many airport taxis always push their cabs to the front of the queue, it could be that the airport wont allow running engines? but i think its fuel saving.

[cowslip]

You wouldn't recll for engine damage resulting from idling as it is not in the manufacturers remit - it is abuse of the engine.

Agreed that nowadays engines - especially diesels are pretty much unburstable but if you haven't got sufficient airflow....that's it.

[Lickey]

And now is the time of year when engines get "seasonal asthma" dry dusty roads, ive never in 6 years seen anybody use an airline to blow crap out of the radiator/intercooler, it should be done from the inside to blow crap away,

Oh yes, ive seen one, me,, airflow is very important for any engine, a good point Cowslip, missed by all,,,

[ClareQuilty]

Back in the old days I used to frequently leave my engine idling for 15 minutes or so to keep the air on, but this was back in the 80s and 90s with cast-iron push-rod V-8s - they really were almost totally indestructible. A friend of mine once broke the ignition on his old Chevy Caprice upon arriving home late in the evening, so he just left it running all night. It was fine in the morning, just sat there idling, using about a quarter tank of gas. I doubt I'd trust a modern car to sit idling overnight.

[cbuddha]

One more habit that i have seen, but this one i have no clue about the reasoning for, is when parking the car on a slope in the person's drive, rather than the usual practice of using the handbrake, using a bag of sand behind the rear wheels. The car i notice in my neighbourhood with which this is done is a brand new Vios, so i can't imagine the owner thinks the handbrake cable is going to snap. It's only a slight incline anyway. Anyone else seen this before?

Maybe he likes drifting and is afraid the parking brake will imprint on the red-hot disks. I personally use a concrete block instead of a sandbag, but that's because there's no room to fit a parking brake after jamming an RB-20 in my old crown.

EDIT: And of course, he must be a master drifter to be getting sideways in his FF Vios.

Edited November 19, 2012 by cbuddha