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How Long An Idle Is OK?
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Author:  yakers [ Sat Jan 17, 2009 2:19 pm ]
Post subject:  How Long An Idle Is OK?
How long can a KJ CRD idle without a problem? I expect to spend some days camping in the desert and I am trying to figure out if i can just run the CRD for its air conditioner for some time during to get through the heat of the day. This would be for maybe 1 to 3 hours. I don't think the engine would overheat but would there be any other wear issues form long idles? I am not concerned about fuel use and there would be no other load on the engine. I could also keep the RPMs a bit above idle if that is a better solution. It would certainly be quieter above idle.
Author:  geordi [ Sat Jan 17, 2009 2:53 pm ]
Post subject: 
I've idled my diesels (VW Jetta and now the CRD) for 8+ hours at a time without any problems. When driving on a long trip, I use my CRD as a portable hotel, and stay in the back of a Flying J with the other truckers.

Running the AC or the heat (as seasons dictate) at just the standard idle has never caused me a problem, and any diesel will automatically reduce fuel to match whatever load is applied to it. Idling the CRD will only use a quart per hour. I proved that on my trip this past summer, I filled up when I got to the truckstop, and filled up again the next morning before leaving - 8 hours, 2 gallons almost exactly.

BTW: The Jetta, after being idled for MANY hours while I worked as a chinese food delivery driver and had 150k miles on it... Had compression of 500 psi in each cylinder - at the top of the "new engine" range from VW's own books.
Author:  MrMopar64 [ Sat Jan 17, 2009 8:51 pm ]
Post subject: 
+1

You can idle the KJ for as long as the fuel tank will keep the engine fed, no problems at all.
Author:  Ripster [ Sat Jan 17, 2009 9:27 pm ]
Post subject: 
Mr Mopar, were there ever any diesels with turbos that without more than idling pressure would allow oil to pass through the turbo bearings
if extended for a long period of time? There are those that have the opinion that extended idling will harm the turbo. Have heard arguements
to that extent, just wondering what you have seen in long term breakdowns.
Author:  warp2diesel [ Sat Jan 17, 2009 9:54 pm ]
Post subject:  Older Diesels ...
..had injectors with an area between the seat of the needle and the discharge holes that would coke up and clog up with carbon. When I was a young wrench, I
would get the job of poking out the clogged up holes with a small wire mounted in a pin vise. Then I would put the nozzle on the pop tester and give it a hard push to blow out the carbon. If the nozzle chattered and had the correct opening pressure it would go back into the engine.

As nozzle machining technology improved they were able to produce low-sac and then sac-less nozzles. Our CRDs have a solenoid version of a sac-less nozzles and are much less apt to coke up from idling. Run good fuel and injector cleaner and it should not be a problem.

Cold idling on the other hand causes excessive ring wear and should be avoided. As soon as I have oil pressure, it runs on all four, and my seat belt is fastened I get going. In the last cold snap here, the dive train oil was so thick that it felt like I was towing my tandem axle trailer for the first mile.
It was cool to see 18PSI boost at 600F EGT when I took my Wife to lunch at -7f just driving in traffic up a gentle hill.
Author:  MrMopar64 [ Sat Jan 17, 2009 10:52 pm ]
Post subject: 
Ripster,

Many years ago when turbo and bearing technology were not as advanced as that of today, it might have been an issue. But with anything made in the last decade, it's not much of an issue.

The worst thing you'll have from extended idling is somewhat of a hydrocarbon stink from the catalyst being cold, but generally after a certain time of idling the egr turns off so it's generally not an issue, especially in the desert.
Author:  geordi [ Sun Jan 18, 2009 5:41 pm ]
Post subject: 
Catalyst? EGR? Oh, on one of those unlucky vehicles that didn't get a SEGR for Christmas... I feel sad for those Jeeps. :P


After the SEGR on mine, I didn't notice any of the stink until I pulled the cat completely. It will irritate your eyes at the back of the CRD... OUTSIDE the truck if you do like I have, but running ULSD or biodiesel cuts down on it a lot.

Sometimes I don't always have a full tank of ulsd tho.
Author:  Coal Cracker [ Wed Jan 28, 2009 12:11 am ]
Post subject: 
I wouldn't idle any diesel for more than 20-30 miniutes. Especially in the winter. Idling leads to cooler cylinders, and unburned fuel in the chambers, thus carboning up the rings, and injectors,valves Also leads to fuel in the crankcase.
you'd be nuts idling 8 hours :shock: . if the engine is hot, and you're in the desert, weel that's a jury call , but cold weather idling for a diesel is a big NO-NO. Food for thought, most truckers don't own their own rigs, so they'll idle all night long. The smart owner operators have seperate heaters that run from fuel, and they'll get at least 800,000 before they have to throw liners at them.
Author:  BVCRD [ Wed Jan 28, 2009 2:57 pm ]
Post subject: 
Coal Cracker wrote:
I wouldn't idle any diesel for more than 20-30 miniutes. Especially in the winter. Idling leads to cooler cylinders, and unburned fuel in the chambers, thus carboning up the rings, and injectors,valves Also leads to fuel in the crankcase.
you'd be nuts idling 8 hours :shock: . if the engine is hot, and you're in the desert, weel that's a jury call , but cold weather idling for a diesel is a big NO-NO. Food for thought, most truckers don't own their own rigs, so they'll idle all night long. The smart owner operators have seperate heaters that run from fuel, and they'll get at least 800,000 before they have to throw liners at them.






I agree. I would be wary of soot buildup, but he could always hammer it up to 3 grand for a few seconds to blow it's nose.
Author:  UFO [ Wed Jan 28, 2009 3:09 pm ]
Post subject: 
BVCRD wrote:
Coal Cracker wrote:
I wouldn't idle any diesel for more than 20-30 miniutes. Especially in the winter. Idling leads to cooler cylinders, and unburned fuel in the chambers, thus carboning up the rings, and injectors,valves Also leads to fuel in the crankcase.
you'd be nuts idling 8 hours :shock: . if the engine is hot, and you're in the desert, weel that's a jury call , but cold weather idling for a diesel is a big NO-NO. Food for thought, most truckers don't own their own rigs, so they'll idle all night long. The smart owner operators have seperate heaters that run from fuel, and they'll get at least 800,000 before they have to throw liners at them.






I agree. I would be wary of soot buildup, but he could always hammer it up to 3 grand for a few seconds to blow it's nose.
Not sure that's a good enough load to qualify as an "Italian tune up".
Author:  Coal Cracker [ Wed Jan 28, 2009 6:27 pm ]
Post subject: 
Well, I don't mean to sound like a smart donkey, but I wouldn't want to be his little tractor if he idled me for 8 hours, then hammered me up to 3 grand,,to clean me out. LOL

When I worked on the railroad we used to see allot of wear on the cylinder liners, and see loads of fuel in the crankcase samples, just from idling a locomotive for long periods

By the way UFO, SEGR IS AWESOME! Workin great 8) You deserve an atta boy
Author:  Diggerfreek [ Thu Jan 29, 2009 12:35 am ]
Post subject: 
Coal Cracker wrote:
Well, I don't mean to sound like a smart donkey, but I wouldn't want to be his little tractor if he idled me for 8 hours, then hammered me up to 3 grand,,to clean me out. LOL

When I worked on the railroad we used to see allot of wear on the cylinder liners, and see loads of fuel in the crankcase samples, just from idling a locomotive for long periods

By the way UFO, SEGR IS AWESOME! Workin great 8) You deserve an atta boy


most cat engines will idle at 650 to 700 rpm and have been programed for machine application to raise idle to 1000 to 1100 during extended periods of time
Author:  grywlfbg [ Thu Jan 29, 2009 12:59 pm ]
Post subject: 
But I thought our engine has a viscous heater that will actually heat the coolant if the engine temp falls too low? That should prevent cold engine wear correct?
Author:  Coal Cracker [ Thu Jan 29, 2009 5:43 pm ]
Post subject: 
grywlfbg wrote:
But I thought our engine has a viscous heater that will actually heat the coolant if the engine temp falls too low? That should prevent cold engine wear correct?


It does have a viscous heater, but it still will not put out enough heat to keep at a proper operating temp, and yes the cat's do have a cold high idle feature, as do the newer cummins dodges.

But as it is the jeeps don't have a high idle, which in my opinion is an aid, and shoudn't be a crutch, and if my diesel had a high idle and a viscous heater, I still wouldn't be idling in the cold.

I love that my vm has a viscous heater, and i chuckle at some who have removed it to save fuel :? , it's purpose in life is to aid the engine in warm up.

Just my 2 cents
Author:  nursecosmo [ Thu Jan 29, 2009 5:48 pm ]
Post subject: 
grywlfbg wrote:
But I thought our engine has a viscous heater that will actually heat the coolant if the engine temp falls too low? That should prevent cold engine wear correct?


No. The viscous heater can only heat the coolant to ~180 degrees f. The vaporisation temperature of D2 is considerably higher, so if any over spray from the injector contacts the cylinder walls (which it does), it does not burn or vaporize, but rather dilutes the engine oil film and makes it's way past the rings and into the crankcase oil. In summer the combustion temp at idle "may" be high enough to keep the cylinders hot enough, but in winter there is no way.
Author:  warp2diesel [ Thu Jan 29, 2009 7:51 pm ]
Post subject:  Problem with high idle in a Liberty CRD
I like blowing away a Big Block Tahoe at stop lights but, having to hold the brake that hard all the time will make my leg cramp up.
Even with my size 13 reinforced toe boots :lol: :lol: :lol: :lol: :lol: :lol:
Author:  geordi [ Thu Jan 29, 2009 8:06 pm ]
Post subject: 
Coal Cracker wrote:
Well, I don't mean to sound like a smart donkey, but I wouldn't want to be his little tractor if he idled me for 8 hours, then hammered me up to 3 grand,,to clean me out. LOL

When I worked on the railroad we used to see allot of wear on the cylinder liners, and see loads of fuel in the crankcase samples, just from idling a locomotive for long periods

By the way UFO, SEGR IS AWESOME! Workin great 8) You deserve an atta boy


You don't sound like a smart-arse, but you do sound like someone trying to equate a MASSIVELY larger engine that does considerably different work with a tiny light-duty high-rpm model.

I understand that trains HAVE to idle for excessive periods, due to some DOT regulations. At least, that was the reason given when a bunch of residents living near a pre-existing trainyard started moaning about there actually being TRAINS in a trainyard. So there is a precedent for long-duration idling on those. Also, the difference in output between no-load and full-load is IMMENSE, not so with our little CRDs. Even further... I would strongly suspect that the average train engine wouldn't know what synthetic oil looked like if you painted the engine with it. Would a beancounter buy Mobil-1 by the tanker for an oil change on one of those? Highly doubtful. The engine has much lower tolerances than our CRDs do, and the pistons can "wiggle" a lot more, I'm sure. That would easily cause your fuel blow-by, as well as the increased wear numbers, with little loss in actual performance at such a large scale. With synthetic oils, the tighter the tolerances, the better it adheres to the mating surfaces. Conventionals can't do that nearly as well.

I know quite a few owner/operators of trucks, and there are two reasons they might not idle their trucks when sleeping: The state has laws against it, so hopefully the truckstop has those window-mount A/C and electric units... Or the insanely high cost of diesel fuel. Even then with the costs, many were still idling b/c they need the a/c to be able to sleep. Not every driver can afford an APU.

Back to our little engines. Please let's all try to compare apples to apples, hmm? I'm not going to equate my 2.8 liter engine to the engine pushing a tanker ship, yet they are both diesels, aren't they? Is a Ferrari engine the same as the one in a Triumph? Didn't think so.

Thats why I related it to the engine in my Jetta TDI - Close in size, close in function. And I've owned both, and idled both for "excessive" periods with ZERO problems. That Jetta? I usually did 12k-15k oil changes, Mobil-1 Delvac (it was a 2001, so it didn't need the 505.01 oil) and after 150k miles of hard driving, long idling, 30k miles of homebrewed unwashed biodiesel... The primary indicator of wear would be a loss (or at least a difference across cylinders) in compression, right?

Compression test: 490psi, 495psi, 500psi, 498psi. All cylinders within 10psi, and at the TOP of the "new engine" scale for VW's own engineering specs.

If I hurt that engine by idling, tell me how. The guy who bought it had an identical car already, and wanted to know what was wrong with HIS, after driving mine. That's all the proof I need, and can ever offer.
Author:  Coal Cracker [ Fri Jan 30, 2009 1:29 am ]
Post subject: 
Well in the fact that I agree that a V-16 3,00 HP GM Electromotive Power unit and the vm motori 2.8 are definately diffrent in some ways, thus not comparing apples to oranges, I 'd still have to classify them both as fruit.

While I can't explain why other diesels blow out cranks and why some 6.2 & 6.5 GM's crack heads,and some don't, or why one person gets 19mi. to the gallon while someone else gets 29. I still have to say I've seen the detrimental affects of long idling in a long array of internal cumbustion engines from gas to diesel, form fleet vehicles to Locomotives and diesel powered equipment.

Even though the cylinder comp, test on your old jetta engine we're in fact great, I would still have to suspect the rings being packed with carbon, that might have even helped your comp ratio, like packing in a hydraulic or steam cyl, or maybe the cyl's washed down with fuel, thus clearing carbon?

The results I've seen are the same, High concentrations of carbon and deposits, and higher wear, due to long Idle times.

I guess I could keep splitting hairs :P , but that's my story, and I'm stickin to it!
Author:  Sir Sam [ Fri Jan 30, 2009 3:13 am ]
Post subject: 
geordi wrote:
[.................Thats why I related it to the engine in my Jetta TDI -.


You @#$@#$@#*@*ing did it didn't you? I warned you but you did it anyways. This was the last straw, the last time you compared the CRD to a VW.

That's it, its on like donkey kong.

Firing Phasers, Mr Laforge.
Author:  Joe Romas [ Fri Jan 30, 2009 10:07 am ]
Post subject:  Boy this sure got off track :shock:
The original question was about the desert in the summer time and running the engine for the Air Conditioning :lol: I really don't think there would be a problem of a cold engine in those conditions :roll:
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