Diesel engine idling

The concern with extended idling is that combustion chamber temperatures drop off (because so little fuel is being used when a diesel's idling), which will result in incomplete combustion, leaving some unburned fuel in the cylinders. This fuel will wash down the cylinder walls, diluting or removing the oil, and cause excessive wear to the rings and/or cylinder walls, as well as contaminating the oil with diesel fuel (over time). This is why on big rigs, they have an "idle up" feature, because guys will idle them for hours on end (especially when it's a cold night).

For our engines, I'd say over 15-20 minutes would be considered "extended" idling, and should be avoided. But for the time it takes to run in and pay for fuel, lunch, restrooms, whatever - not a problem.

It's a good idea to let a diesel idle for a few minutes to let the turbo cool down before shutting the engine off.

On my 04 600 the owner's manual explains it. It also says if you do let it idle for an extended period of time the idle will go up to 1,000 RPM to try to keep the combustion chambers warm. Some years ago a Diesel mechanic told me prolonged idle carboned up the injectors....

Al

And the starter is spared another cycle.

Won't matter in a few years anyway. Many states are enacting laws to make it illegal to idle ANY diesel for more than 5 minutes. Already law in New York and Cal. I believe it is in PA as well.

LOL, yet another law that is just about impossible to enforce.

So I guess the bottom line is, for a quick pit stop, letting it run is actually a good idea. As long as you don't lock yourself out or somebody steals it. If you plan on stretching or napping a little...shut 'er down. Now all I have to do is keep an eye out for the deputy who'll keep us safe by writing up an "illegal idling" citation. Dang...what next? I got pulled over two weekends ago doing 58 in a 55 zone by a highway patrolman who says he clocked me doing 70!!! The only way I dodged getting a ticket is he tried to tell me my driver's license expired too...I had to tell him this was still March and my license expires in April. ("Wellll...I'll let you go this time.")

I wish somebody would modify the ECM program so you could hit the cruise control switch and set the idle using the accel/decel controls when the truck is not in gear. That would be a great feature if you were running something on a PTO.

Greg

I'm real paranoid about locking the truck while it's running. I can use the key fob to lock and unlock the doors in most cases, but I discovered (without the engine running, fortunately) that there are some parking areas on the Navy base where I'm stationed that the key fob doesn't work - particularly next to the schoolhouse where they teach maintenance on the radar and satellite communications systems. ;-(

Greg

I take it you carry a chocklate bar in your shirt pocket and turn around whenever it begins to melt?

Use to run into that problem sometimes when parked on the pier. Especially if a carrier was in port. I don't think they ever shut down their radar. Anyway, discovered if I walked up to the truck and placed the fob next to the door glass it would work ....... most of the time :)

Jerry

Yeahbutt . . . it only takes that one call to the SO to bring another set of keys from home and she'll NEVER let you forget it! ;-(