Idling Diesel ??

I don't blame anyone for wanting to take the best of care of their diesel engines. However too many are confusing pickup trucks and recreational vehicles with commercial over-the-road tractors. They may all burn diesel fuel but that is all they have in common.

There is big difference between idling cold engine with no load and idling hot engine to keep the heat.
Observe that lot of semi truck, when idling overnight for heat have their lights on.
The overnight engine idling with truckers is a topic active for generations.
Common experience is that the procedure is common with hired drivers, while owners-operators don't do it.
I think some truckers can't sleep in quiet environment as have heard the engines idling in 70F nights.

eHoefler wrote:
In newer desiel engines that have particulate filter, idling can cause premature failure, which is not covered by any warranty. A Ram DPF cost upwards to $3,000 plus labor.

On a Cummins 400ISL the cost is close to 5K.

The Cummins dealer told me I had high idle time. I do not idle much except to air up but have when stopping for lunch or fueling so I did some mental calculations and have to agree. Highway time versus idle times when doing small trips can add up.

Not only is there a good reason, for some coaches it is absolutely essential!! That is building air pressure in the air suspension. Many coaches (mine, for one) dump air pressure prior to deploying the leveling jacks (not optional). It is necessary to pressurize this system before moving. It doesn't take very long (never timed it but guess 5-7 minutes) but probably long enough to annoy some folks.

If I do idle, I do a fast idle at 1100 to 1200 rpm. This makes a better combustion process and is better for the engine.

Old-Biscuit wrote:
Difference is Knowledge!

A idling diesel will NOT come up to temp
Idling a diesel causes unburned fuel to wash down piston cylinder walls
Unburned fuel can get into turbo and/or crank case

No GOOD reason to idle except to allow motor to cool down after a hard run....which would be 5 minutes or less
Idling at start up is not necessary or worthwhile


By the way.....
Size....HP/Torque not much different either

This about sums it up. I have a digital temp gauge and can tell you that after running down the highway with the temp right at 187, I can pull into a rest stop, let it idle and within a minute, the temp has dropped to 175. If I let it idle longer, it will drop all the way down to 170 and stay there. Even after the "long hard pull" that everyone talks about

How times change.. When I was a teen ideling of Gasoline engines for more than a minute or two was not recommended cause the plugs would foul. In fact when I went to work for the State of Michigan at 27,, One of the things that was common on the freeway was for suspects to rabbit (HIT the gas and try to flee) when the troopers "Lit 'em up" (Turned on the police lights) because the city police cars which normally operated the streets at low speed... Well the plugs fouled and when they tried to catch the violator.. The engine would buck, stutter and stall often as not. (Sadly for the violators the State Police cars did not have that problem since they only traveled about 3 blocks on surface streets then HAMMER DOWN time on the freeway)

Diesels of that era however could idle all day no problem

Today... Thanks to modern Engine Control Comptuers, Gasoline engines, can idle all day (in many cases) no problems (Some of the big ones may overheat)

Diesels, however,, have a need for speed (more than idle).

The proper warm up time for all engines is the same.

Start engine,, Buckle seat belt, Engage and SLOWLY drive out of campground.

By the time you hit the road, you are warmed and ready to hammer down.

In the past OTR idled the engine for heat or air. Newer trucks are coming with a APU for that when stopped. Today it's more an invironmental thing than engine wear.
By the time you get out of the CG the Diesel engine is warm enough to go to work.

In newer desiel engines that have particulate filter, idling can cause premature failure, which is not covered by any warranty. A Ram DPF cost upwards to $3,000 plus labor.

The only idling we do is prior to departing to build up air tanks. This takes about 5-6 minutes. Applicable only after longer stays at a campground. Overnight tanks keep volume of air sufficiently as to not set off low air alarm.