Idling diesel engines

BCO

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My truck driver tends to start up our truck and let it idle for 15-20 minutes each morning. I'm pretty sure that this is not good at all, but I wanted to be 100% certain before I tell him not to do it, as I'm sure he's going to try and tell me that it's good to idle the truck in the morning. Any info on this?
 

LCBXX

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Unlike petrol engines, a hot diesel engine cools when idling.

Starting and idling a big diesel would only result in it warming up a little and circulating the oil. 5min should do it, 20min is overkill IMO.

Read the truck's handbook. It will tell you what the correct cold-start procedure is.
 

JK8

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Its better to make sure the oil is warm before driving. Also if its a turbo diesel, the turbo should "wake up"


If the truck is not warm and he needs to use more torque when climbing a hill, he wont make it.

Maybe 15 minutes is to much, but more than 5 is about right.
* all cars should be warmed up before you drive... over 4000rpm.
 

Palimino

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My truck driver tends to start up our truck and let it idle for 15-20 minutes each morning. I'm pretty sure that this is not good at all, but I wanted to be 100% certain before I tell him not to do it, as I'm sure he's going to try and tell me that it's good to idle the truck in the morning. Any info on this?

Diesel engines are **meant** to run at a constant rpm for extended periods (that’s what they are built for) – generators, tractors, etc. There’s probably a slight difference with an engine designed to be controlled by a throttle. If the oil circulation and cooling are OK, there is no problem.
 

Fazda

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No problem at all, the old diesel will enjoy it in fact! :D
 

Nokkie

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My truck driver tends to start up our truck and let it idle for 15-20 minutes each morning. I'm pretty sure that this is not good at all, but I wanted to be 100% certain before I tell him not to do it, as I'm sure he's going to try and tell me that it's good to idle the truck in the morning. Any info on this?

I agree with Icbxx 5mins is more than enough
 

plazma

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Diesel engines are **meant** to run at a constant rpm for extended periods (that’s what they are built for) – generators, tractors, etc. There’s probably a slight difference with an engine designed to be controlled by a throttle. If the oil circulation and cooling are OK, there is no problem.
:confused::eek::confused:

The problem is that he is wasting fuel by letting the truck idle for much longer than is necessary. Not to mention the wear and tear...
 

LCBXX

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According to my car's computer, idling the engine uses 600ml of diesel per hour.

A 4-liter diesel engine should then use about 1.2L of diesel when idling per hour.
:confused::eek::confused:

The problem is that he is wasting fuel by letting the truck idle for much longer than is necessary. Not to mention the wear and tear...
 
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Palimino

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:confused::eek::confused:

The problem is that he is wasting fuel by letting the truck idle for much longer than is necessary. Not to mention the wear and tear...

Yeah, but it’s negligible. The fuel wasted? and the wear and tear? must be traded-off against a warm engine with oil circulated throughout. Wear and tear will be minimal (the engine is not under load) and leaving the truck idling could be a parallel-processing tactic. The driver starts the truck and leaves it idling while he completes the inevitable paperwork (delivery schedules, destinations, etc.). Completed, he climbs into his, already warmed-up truck, and starts off straight away. The driver knows what he is doing. Don’t interfere with petty druthers to save 50 cents worth of diesel over a year.
 

ponder

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Actually it's just that the truck parks outside my office window and it pumps ****loads of fumes at me each morning while idling. :p

Understood on the fumes thing, cannot stand it myself. Tell hime to park somewhere else.
 

risingtide

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Starting and idling a big diesel would only result in it warming up a little and circulating the oil. 5min should do it, 20min is overkill IMO.
Surely it doesn't take 5 minutes to circulate the oil? What is the difference between idling @ 800 rpm and driving @ 2000 rpm? (I know it is 1200 rpm, saving you posting it). Both put a negligible load on it.
 
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Gnome

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When it comes to cars I say don't let it idle because it's a trade off between the heat-output at low RPM VS the wear at that RPM, so I feel that it takes such a long time to reach the optimal temperature just sitting there it's probably causing as much if not more wear than if you just drive it outright. Not anything crazy but low load, low rpm until the oil is hot.

On a truck on the other hand, they only go up to around 2000rpm so it's likely best to let it idle.

As mentioned before a engine wears more in the few minutes it is cold, I actually read that it wears more in those few minutes it's cold when you start it up then it will with you driving it to Cape Town from Johannesburg when the oil is warm.
 

Fazda

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Comparing cold diesel engines and cold petrol engines is totally different. The petrol engine is happy to gently warm up whilst being driven carefully when cold. The diesel NEEDS to be warm before driving...it's the nature of the beast. Warming it up will more than likely IMPROVE fuel consumption per tank anyway, as the fuel used during warmup is minimal, compared to that used whilst trying to drive the poor bloody truck when it's cold.
Just tell him to warm it up otside someone else's window BCO :D
 

UtterNutter

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:confused::eek::confused:

The problem is that he is wasting fuel by letting the truck idle for much longer than is necessary. Not to mention the wear and tear...
Diesel engines are highly efficient at idle speeds. That is why large diesels such as in diesel-electric trains don't even get switched off, they just idle over weekends and the like.
 

appels

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if you say truck, how many tons? air tanks on the truck needs to be fulled to release brakes
 
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