ive always heard that its cheaper to let a diesel run for a while longer, than it is to shut it off for a few minutes and restarting it. (ex. running in to the grocery store for a few minutes.) is there any truth behind this? im looking into possibly getting a diesel, and was surprised to hear that they are so fuel efficient.

 

It's not cheaper, it still uses fuel.

The problem with prolonged idling is a condition known as wet-stacking. This is un-burnt fuel that can coat valves and whatnot and cause problems down the road. I've let my truck idle every now and then, but not more than just a few minutes. Normally I just shut it off and run inside the store or whatever.

You do want to let a turbo diesel idle for a period of time after driving it for a while before shutting down. The reason is to let the turbo cool down so that after shutdown hot oil doesn't coke on the bearings. If you have a pyro, letting the temps settle to around 300 degrees or so is ideal for shutdown.

 

ah, that makes a lot of sense. and i've read a lot of threads on diesels, and havent heard about letting your turbo cool down...thats a lot of good information. really appreciate the help.

 

UPS and FedEx start and stop 'em 50+ times per day. No real issues.

It ain't 1950 anymore. Shut it off. (of course if you just pulled a hill with your own truck you would spool the turbo down)

 

Also it aint 1980 anymore and since we drive computer controlled engines, wet stacking is not the problem it used to be in the early years. especially if you live in the southern climate. My 99.5 has over 220K on it and it idles for two to three hours a day( it is my mobile office ), and I have never had an issue.
this subject has been discussed before on this board and other boards, the consensus is if you want to be sure add an idle contoller to your truck for long periods of idleing.

Now as far as cheaper to idle than start, thats one of those questions that nobodys for sure on, I dont' think you or I would actually notice the savings (if there are any) it would be such a small percentage that it would probably take hundreds upon hundres of thousands of miles to realize any difference.
Just my .02

 

Mine has seen as more then 8 Hrs of idle time during a day MANY times and gets shut off when I stop and am done with it. No cool down time. Over 364,000 miles with no problems from ideling or shut downs.

 

Good Point 85e150six4mtod about the FedX and UPS. Anyone know what engines they typically run and what weight are their box/step trucks rated for?

 

The Fedex Express trucks run a Cummins with an automatic, and seems like max payload is 6000lbs in those, GVW maybe 16000???? Those are the 700 Cu Ft models. There is a 900 as well. Newer ones have a 5 gear auto.

UPS has some Cummins, or so it sounds, but runs manual trannys. They run a little larger truck on average. Not sure about payload.

Both outfits have a variety of trucks as the order of the day is to run the wheels off them. Some are real penalty boxes....

Both outfits have Sprinters also. Nice truck, but like a doll house compared to the bigger trucks.

 

Very good Point 85e150six4mtod about the FedX and UPS. Must be a reason the big corporate guys tell their drivers to turn the trucks off at delivery stops which are using for a short duration. Has to be a money saver some how.

 

One thought about the UPS trucks being shut off at each stop.....assuming they remove the key too....limits opportunity for someone to jump in and drive off with the truck....happened to my father .

 

It's becoming illegal in more and more states to leave vehicles running unattended.

Why give that cranky officer at 7-11 for first cuppa coffee a reason to give you a ticket?

But more to the point,

Think about driving to the grocery store in your shiny new Power Smoke and running inside for that proverbial six-pack and leaving the truck running.

While you're inside the loser in the lot that watched you come in runs up to your cool truck with a spring loaded center punch and breaks the passenger side window (or the rear window from inside your really neat camper shell) and jumps in and drives away because you so conveniently left him not only the keys to your new truck but also the keys to your house and your address and everything else you left in your truck!



I wouldn't make it so easy for these guys. If you did a hard pull, let it idle at the stop light and drive slow and easy in the parking lot, let it idle a few min and SHUT IT DOWN.

Then lock it and take your keys. The first thing the insurance company asks is "Was it locked?" and/or "did you take your keys?"

Cheers,

Rick

 

i have a 93 350 van, should i let the van idel for awhile befor i shut it off?
does that help cool down?