Letting truck idle

mkirsch wrote:
Someone hit on this earlier, that the practice of leaving diesels idle comes from the fact that in the early days, they were hard to start. The engines were low-compression, had no glow plugs, maintenance wasn't priority #1, and the starter/battery technology of the time just couldn't crank the engines over all that well. Once you got 'em running you left 'em running until you were darned sure you were done using them for the day.

Today, the big-riggers can't even leave them running anymore. Many trucks made in the last 15 or so years automatically shut off after so many minutes of idling.

I agree. I have always been told that it stems from the 50s and 60s when diesels were hard to start, fuel was cheap and electric starting systems were not very effective or durable. Another factor may have been that most diesels were commercial and the guy running it didn't have to pay the fuel bill or the overhaul bill. Those old truckers were definately set in their ways. I remember how hard it was to get them to give up the noisy cross bar treads on the drive tires. Those tires also gave less fuel economy.

As far as leaving a modern engine running, I would like to get some clarification on the impact to the diesel exhaust filter. I know that my 2013 motorhome with a Cummins diesel says not to let it idle for "an extended period". Once when my generator was acting up and I needed to run the main engine to get electricity I called Cummins and asked how long I could let it idle and was told up to 12 hours. On the other hand, I have heard to ambulances and fire trucks have had some issues when idling and some are going back to gasoline engines.

I thought the older rigs used compressed air starters and not electric. Many of them would idle once started to refill their tanks (allowing them to release the brakes and raise their suspension). Operators were used to idling the engines before shut down to ensure that the air tanks were pressurized enough to start the engine again.

Someone hit on this earlier, that the practice of leaving diesels idle comes from the fact that in the early days, they were hard to start. The engines were low-compression, had no glow plugs, maintenance wasn't priority #1, and the starter/battery technology of the time just couldn't crank the engines over all that well. Once you got 'em running you left 'em running until you were darned sure you were done using them for the day.

Today, the big-riggers can't even leave them running anymore. Many trucks made in the last 15 or so years automatically shut off after so many minutes of idling.

FishOnOne wrote:
There's been a sign crew working on putting up new intersection lights running two F550 6.7 trucks. Last week I went by them at ~7:00am and the trucks were idling. Came back by the house ~12:00pm and the trucks were still there idling.

As for idling my truck I use the remote start during the hot summer months and start my truck in advance so when I hop in it's nice and cool. I idle it at gas stations. I also use the timer on the remote start to cool the turbo off after a hard pull and then the truck shuts off. I idle at the deer camp a lot when we hunt. I think 25 percent of my total engine hours is basically idling.

Their trucks probably have PTO-operated cranes or winches, etc. The truck engine needs to be running to operate their equipment. Most commercial service trucks with cranes, manlifts, wire pulling winches, etc, will run the engine all day long while working on the job site. The PTO controller has a high idle speed function that can be set to various speeds, according to engine power needs of the equipment being run.

It's rare that I have a hard pull and then am stopping somewhere immediately. The truck is not working that hard just pulling a load down the interstate or through town that I need to worry about the EGT. The only time I let mine idle is if we pull off to a lookout on a mountain pass we are climbing.

Stupidity should never be mistaken for ignorance. The latter can be fixed, the other, not so much.

rhagfo wrote:
Old habit, but if they only leave for about 5 minutes or less, allows the EGT to cool down, rather than a hot shutdown.

Today many Turbos are water cooled, where older were air cooled, best to let idle for a couple minutes before shutting down.

I'm the same way when towing. If I'm pulling at higher speeds and pull right off the road into a fuel station, I leave it running for about 5 minutes to cool down the turbo. If I'm just getting fuel and leaving (no potty breaks for the little ones) then I leave the diesel running while I get fuel. When I get to the campground and am dropping my camper, I leave it running while I unhitch, then I park it and finish setting up.

My manual clearly states to let the truck idle to cool down EGT's before shutting the engine down.

salem wrote:
A friend of mine always lets his 2500 diesel idle while he makes a short run into the post office, store for a quick soda, etc. He says the salesman told him that starting and restarting a diesel was the worst thing you can do. Of course he locks it up, but I have never heard of this. Is this common practice?

:) Hi, surely this person could drive his wife's car for short errands. Well, the one time that he forgets to lock the doors, or someone breaks his windows and drives off with his Kenworth, he won't do that anymore.

Trackrig wrote:

Lessmore wrote:
I've seen some let their diesel idle while filling up at a gas station. Signs at service stations say to shut off while refueling. I note that the big tanker trucks that fill up the service station tanks, shut off while at the stations.

I don't know why some drivers in diesel pickups let their trucks idle...everywhere.

Because they want to make like a "big diesel truck driver"?

Bill

:) Hi, yes; I call them "Joe Kenworth".

There's been a sign crew working on putting up new intersection lights running two F550 6.7 trucks. Last week I went by them at ~7:00am and the trucks were idling. Came back by the house ~12:00pm and the trucks were still there idling.

As for idling my truck I use the remote start during the hot summer months and start my truck in advance so when I hop in it's nice and cool. I idle it at gas stations. I also use the timer on the remote start to cool the turbo off after a hard pull and then the truck shuts off. I idle at the deer camp a lot when we hunt. I think 25% of my total engine hours is basically idling.