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View Full Version : Idling Diesel Engine am I doing any harm to my engine?


GringoPhil
12-10-2012, 05:19 PM
Hi All,

I'm in a very nice but shade-free RV Park & I don't run the engine constantly, but perhaps 1/2 hour on and 1/2 hour off, between about 11:00 A.M. until 6:00 P.M. The sites here are spacious and I'm quite sure the exhaust isn't bothering anyone (If it was, I would stop doing this, of course). What I am wondering is, am I doing any harm to my engine? All the gauges have remained dead center (temp, oil pressure, etc.) and after several hours, the fuel gauge hasn't budged.

Asking for opinions,

Phil

Chester B. Stone, Jr.
12-10-2012, 05:26 PM
You should increase the speed to 1,000 RPMs. If you idle at say 600 RPMs, excess diesel fuel will wash oil from the cylinder walls, causing damage.

MrE
12-10-2012, 05:58 PM
If you have a DD 2 stroke, I've been told that excessive idling is not good for them.

GringoPhil
12-10-2012, 07:24 PM
Thank you Chester I was unaware of that.

Jon, Its a two stroke

GringoPhil

DavidBall
12-10-2012, 07:33 PM
I agree excessive idling is not recommended. Now from a neighbor perspective, I'm glad I'm not parked next to you :o I'm not a big fan of diesel exhaust.

DB

Newellin Thunder
12-10-2012, 07:50 PM
One of the biggest reasons not to idle a diesel is called "diesel wash". Modern diesels run very cold. Without sufficient heat in the combustion chamber the fuel does not get thoroughly burned. That results in the unburned fuel "washing" the sides of the piston sleeves of the lubrication that is necessary to keep the piston rings sliding easily. That friction causes early failure of piston rings and premature and excessive scaring of the cylinder walls.

Ron in South Dakota
12-11-2012, 02:11 AM
It used to be that over the road truckers would idle their engines for long periods, sometimes for hours on end, at truck stops and some other places. So what has changed in diesel design/construction to make it now a bad idea?

Ron

The Newell
12-11-2012, 02:24 AM
One caution for this thread: "idle" and "fast idle" (about 1000 RPMs on most diesel engines) are not the same in terms of wear and lubrication concerns.

I've seen (or rather heard) truckers run their engines all night when its cold to keep the cab warm. Have always wondered about that in light of the numerous warnings about long idle times. On the other hand, truckers are human and Just because they do something doesn't make it a good thing. Besides, if my choice was freezing my butt off or causing some extra wear on the engine, that engine is in for a rough night!

fulltiming
12-11-2012, 05:06 AM
My question is the underlying reason you are doing this. I know you must be doing it to solve some issue and I would like to know what that is. If it is keeping the batteries charged, you would be MUCH better off running the generator for a couple of hours then shutting it down and running it for a couple more hours. Generators have a load on them when they are recharging the batteries and providing power to the coach. The engine, by comparison, has virtually no load on it. It is a good idea to minimize the amount of time a diesel engine is idled. The owners manual will typically warn you to minimize idling. The generator engine runs at a constant speed (typically 1800 -2400 rpm depending on the generator) and uses significantly less fuel per hour than the 8V92.

GringoPhil
12-11-2012, 05:26 PM
My question is the underlying reason you are doing this. I know you must be doing it to solve some issue and I would like to know what that is. If it is keeping the batteries charged, you would be MUCH better off running the generator for a couple of hours then shutting it down and running it for a couple more hours. Generators have a load on them when they are recharging the batteries and providing power to the coach. The engine, by comparison, has virtually no load on it. It is a good idea to minimize the amount of time a diesel engine is idled. The owners manual will typically warn you to minimize idling. The generator engine runs at a constant speed (typically 1800 -2400 rpm depending on the generator) and uses significantly less fuel per hour than the 8V92.

fulltiming,

I start the coach twice a day to keep it level because a couple air bags are bleeping off.

Phil

folivier
12-11-2012, 08:17 PM
Phil, sounds like you don't have a built-in 120volt air compressor to keep the air up?
How about picking up a small air compressor from Lowe's or elsewhere and plug it into the quick connect in your engine bay (assuming that you have that fitting)?
That should keep your air bags aired up.

fulltiming
12-11-2012, 08:51 PM
It really helps to ask "why". I would not have thought about leveling being the issue. You have a significant air leak in the leveling system. I think I would start by hunting down that leak. Once I level, I can shut down my engine and the 120 volt compressor and even though the auxiliary air supply will leak down in a matter of hours, the coach will stay level for weeks. You either have a major leak that should be fairly easy to find since you are leaking a lot of air OR you have a LOT of small leaks. I would first spray the six packs (leveling valves) with soapy water to see if air is leaking out of the system there, then spray the air bags with soapy water, then the air lines from the air bags to the tanks, then the tanks themselves. If you aren't in a position to do that at this time, Forest's idea of adding/using a 120 volt air compressor to keep air in the system to keep it level would be much better than running the engine every hour or so. I am amazed that you would be leaking so much air that you are having to run the engine air compressor 50% of the time to stay level. Does the system hold air when you leave it in the travel position rather than the level position? That will help focus the most likely locations for the air leak.