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Author Topic: Owner Manual Warning about extended idling  (Read 698 times)

Jack W Hannah

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Owner Manual Warning about extended idling
« on: February 11, 2019, 04:51:27 PM »
The manual for my 2002 Patriot states...........
"Idling for more ten minutes can lead to fuel not burning completely and may cause problems with the efficiency of the engine."
Can someone please explain this warning?

Thank you.
Jack W Hannah
2002 Patriot 40B, Monticello
Cat 3126, Magnum Series B

Mike Shumack

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Re: Owner Manual Warning about extended idling
« Reply #1 on: February 11, 2019, 05:18:08 PM »
See this video on engine idling
https://www.youtube.com/watch?v=hvfMal5fReA
- Mike

'05 Beaver Patriot Thunder, Vicksburg, CAT C13  525HP, Allison 4000MH, HydraLift
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Pat Long

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Re: Owner Manual Warning about extended idling
« Reply #2 on: February 11, 2019, 06:54:41 PM »
If and when I idle my coach I always kick it up to 8-900 rpm via my cruse control.   I have done this for Years and have Never Had Any Problems, even on my Rig at work with a Cat C15.  But then there again on Both, there is NO smog systems and or ARD head, DEF, DPF.   Would NOT have a rig with any of those, or even a Cummins.
42' 2000 Marquis Amethyst   Hurricane Heater  Meritor Disc  Silverleaf
Allison HD 4060 C12 425 hp   Southern California
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Lee Welbanks

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Re: Owner Manual Warning about extended idling
« Reply #3 on: February 11, 2019, 09:20:26 PM »
I don't very often idle my coach but if I do I set up the idle with the cruise control to around 900 or 1K. Most if not all class 8 trucks now have shut down timers and some of them cannot be overrode, Calif will ticket you if you are caught idling too long.
There really is no reason for one of our coaches idling longer than a cool down IMHO, just a waist of fuel.
Lee, Judy  & Pepper
06 Beaver Patriot Thunder
Wilmington IV 40
525 Cat, 4K Allison
2013 Honda CRV
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Dave Atherton

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Re: Owner Manual Warning about extended idling
« Reply #4 on: February 12, 2019, 03:32:32 AM »
Lee thank you, yes damage has and will happen with extended idle time with Caterpillar
electronic engines. Information is posted in you engine owners Manual. Extended peroids
of engine idling will glaze the cylinder walls, ( we ask why ) your engin cooling system and
deep reduction fans. Engine heat running cold will create soot build up which will cause
the breaking down of additives that make up your engine oil. Before the entry of the electronic
engines and  going back to the non-electronic engines, the practice was to increase the engine
Idle speed and idle for very long extended periods without any problems but that was back than.
Today we cannot follow that practice any more with our electronic engines.
Dave Atherton Retired Cat Mechanic
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Bill Drout

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Re: Owner Manual Warning about extended idling
« Reply #5 on: February 12, 2019, 11:37:06 AM »
Hi Dave,
   Thanks for your input.  So are you saying that idling even at 1000-1200 RPM should be something that we should avoid too?
Bill Drout
1998 Beaver Patriot Monticello - 40'
CAT 3126B
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Fred Cook

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Re: Owner Manual Warning about extended idling
« Reply #6 on: February 12, 2019, 12:53:13 PM »
Hmmm.... never thought about idling for a long period, why do people do it?? It’s very annoying especially in a crowded RV Park.  I just idle long enough to air up and I’m gone.
Fred & Cindy
2002 Beaver Patriot Thunder 455 CAT
40 FT, 2 Slides, Towing 2012 Mazda III
South Central Missouri, US Army Retired
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Dave Atherton

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Re: Owner Manual Warning about extended idling
« Reply #7 on: February 12, 2019, 02:06:16 PM »
Bill and Fred, cannot fault anyone on different engine practices. There is lots of information
today being passed around the campfire so to speak on many subjects with operation of a
Diesel engine. My background with Diesel engines and providing technical information on
the forum is just my opinion that can be backed up with factual input starting with your operation
maintance manual. Today with the very high repair cost or many times,  the out of
box ideas do not fall into correct operations for long life on your engines. This extended
idle time as some may question, your answer to this question can be found with oil samples at each
service time starting with high soot particle count. Dave Atherton Retired Cat Mechanic
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Bill Drout

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Re: Owner Manual Warning about extended idling
« Reply #8 on: February 12, 2019, 02:31:51 PM »
I'm just trying to gather knowledge.  I'm not suggesting anyone should idle for a long time, and I personally don't idle the engine long by itself.  I can see a situation where the RV is being stored/repaired and is not able to move and where someone might think it's a good idea to start and run the engine periodically.  So I'm trying to find out if that's a bad idea even at a higher idle speeds in excess of 1000 RPM's.  The CAT 3126 operations & maintenance manual seems to indicate that this is okay.
Bill Drout
1998 Beaver Patriot Monticello - 40'
CAT 3126B
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Gerald Farris

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Re: Owner Manual Warning about extended idling
« Reply #9 on: February 12, 2019, 03:02:49 PM »
Fred,
Very high idle times have never been a common problem with motorhome engines, but it was in trucks, especially with company drivers who were not paying the fuel and maintenance bills. It was common for a truck to pull into a truck stop or rest area and let the engine idle all night to furnish air conditioning or heat to the cab and sleeper area so the driver could sleep more comfortably. The need to stop this practice lead to the development and installation of APU (auxiliary power units) and diesel heaters (Webasto or Espar) on many HD trucks, and idle time restrictors in the ECM programing of almost all HD diesel engines.

Gerald   
2002 Solitaire (2017 -  )
2000 Marquis, C12 (2004 - 2017)
1993 Patriot  (2000-2004)
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Lee Welbanks

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Re: Owner Manual Warning about extended idling
« Reply #10 on: February 13, 2019, 01:59:32 AM »
Gerald I couldn't have stated it better, years ago with the old non electronic motors in trucks we would idle for heat and cooling when trying to sleep. I've done a bit of digging in a few of the trucking forums on the newer ECM motors in class 8 trucks and with most of them the auto shut down cannot be overrode unless the ECM is reprogrammed.
Now with our coaches I don't think any of them have a shut down timer, and there isn't any reason in our case to have one idle for any length of time.
Lee, Judy  & Pepper
06 Beaver Patriot Thunder
Wilmington IV 40
525 Cat, 4K Allison
2013 Honda CRV
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Eric Maclean

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Re: Owner Manual Warning about extended idling
« Reply #11 on: February 13, 2019, 03:29:51 AM »
In recent years the engine control modules are equipped with auto shut down to avoid excess idling to comply with emission regs
however most systems can over ride the the auto shut down  by setting the fast idle using the cruise control switches.

Eric
1997 Patriot Yorktown
3126-B
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Eric Maclean

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Re: Owner Manual Warning about extended idling
« Reply #12 on: February 13, 2019, 04:38:38 AM »
Dave is correct the extended idling can cause cylinder wash down This is due to the mere fact that a diesel engine is a compression ignition engines which rely on the heat of the compressed air to ignite the fuel atomized in the cylinder.
The problem with idling is that the cooling systems in these engine do a very good job at moving the heat away from the cylinder liners, at idle this becomes a problem as the outer area of the stroked cylinder is chilled below the kindling point of the fuel ( this area is known as the quench area ).
 As the engine idles because there is no power requirement the fuel delivery and there fore heat produced is minimal which allows the quench area to be more pronounced  this in turn cools the fuel in that area to the point it does not burn and collects on the cool cylinder walls which washes the oil away from the piston rings  reducing cylinder sealing  (lack of ring to cylinder wall seal) and will over time lead to cylinder wall glazing ( a polished condition which deters ring sealing).
 Known as wet stacking because in the older mechanical injection days it could actually get bad enough that you would see raw fuel collecting in the exhaust stack.
 Although today's engines are have far better fuel management systems they are still compression ignition engines with the same inherent problems.
By  raising the idle speed the theory is that the cylinder temperature will increase to the point the quench area is decreased and this is true to a certain extent but you must remember that with out a demand for power the fuel delivery is still minimal and therefore the heat generated is also minimal ( in short idling for a long period  is not a good practice and that's why it is in most manuals as something that should be avoided.

Eric
1997 Patriot Yorktown
3126-B
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