Stopping & Restarting

[Cavalier]

Is it a myth or does excessive stopping and restarting damage the diesel engine, specifically a Duramax. If a person encounters situations in which a diesel is stopped and restarted as many as 12 times or more in a 4 hours period, is the problem here, hard on starters, hard on batteries or the consumption of fuel on startup?

[Kennedy]

My starting/stopping dependson the situation.

If I am on a trip and pull into a rest area, I'll let it run. If I stop for a meal, I'll let it run for about 7 minutes with my remote timer.

If the engine is cold and I'm making a run to the store I will let it run. If it's really cold or hot outside I'll also let it run quite often dependimg on the length of the stop. If it's a short stop I let it run. If long I will not

If it's mild out, and I'm just running around local, I don't let it idle much.

I should note that I have a remote start and use the manual takeover to allow me to keep it running without the key and risk of being stolen. This also times out at just past 20 minutes (26 I think) which is quite handy too.

[LanduytG]

I can't remember if it was Cat or Cummins that did a test on this very thing. Truck drivers like to let them run all the time. But it was proven that you had less wear by stopping and restarting when needed.

Now with that said if the truck is cold I will let it run, if hot after towing I will let it cool down to 400* egt before shutting off. Otherwise I always shut it off.

I have been in the Delco Remy plant in Anderson, IN where they put starters through a test cycle. What happens is they automatically start and stop the motor 24/7 till the starter fails. A cycle will take about 1 minute so its starting and stopping about 60 times and hour. They told me they have had starters go for over a year before it quit.

SO IMHO it won't hurt a thing and you will have less wear other than the starter.

Greg

[fire22dirver]

How about the high idle feature on the newer D-max. And how many of you plug in the engine block, and how cold outside before you plug in??

[Cavalier]

Thanks for the input. I don't have a problem with leaving the vehicle running when I can, and I do. But my unique situations that I encounter requires that I actually must shut the engine off many times a day, as many as 6-8 times an hour. That is why I have raised this question.

[Kennedy]

How long is it shut down for? at 6-8x/hr, that's pretty short. I'd consider leaving it run.

Can you safely and securely leave it run?

[Cavalier]

The situation requires me to shut off the engine and those off times run anywhere from 5 to 20 minutes off and back on, but for the hours for this endurance is generally 4-6 hours not 6-8 hrs.

[carco]

Once upon a time, in the good old days of college, in an ag engineering class we were told that 90% of the cylinder wall wear occured during the first 5 minutes of a cold startup of the diesel engine. This was a cold start, not a luke warm , warm or hot start. Now this was in the 70's, and the diesels tested were farm tractor engines I believe. Todays engines may be a bit different but prob not much. bob.........

[madmatt]

I can't remember if it was Cat or Cummins that did a test on this very thing. It was Cat. During every warrenty repair done on all late model, computer controlled engines a print out of certain running parameters must be printed and submitted w/ the claim. If it is a fuel consumption, noise, or oil consumption complaint the first thing they want to know before you ever get started is Idle time and percentage. They will deny a claim in a second if idle time is to high, though I can't remember what those magic numbers are.

[ 01-17-2006, 01:55 AM: Message edited by: madmatt ]

[Albee]

Fire22, I have my elevated idle turned on. I plug in the truck if it is going to get below 20 above. I have started it at just above zero without being plugged in. Started fine, but don't think too good on her. Good luck.

[markrinker]

There are definately more Duramaxes being stolen in Chandler, AZ every day than Loyal, WI. :D I lived at 29th and Thomas (Phoenix) from '85-'89. You could get the basketball shoes stolen right off your feet.

If you are doing the driving in Arizona - my thought would be to continue the start/stop method as your average outdoor temps aren't cooling down the engine much, and you start each day with free flowing oil anyway.

On a cold day up here in Minnesota, I'd probably let it run - as much for the heated cab when I returned as the wear and tear on the starter.

Conversely, in Arizona's July heat with your A/C cranked and recirculate button ON, I'd let it run and enjoy it - but definately find a way to lock her up while you are gone!

[02RedDmax]

I have read a article in an ag publication talking about diesel engine life. The guy that wrote the article was a long time diesel mechanic. This guy worked on everything from diesel locomotive engines, to big field farm tractors, to small compact diesel tractors. The one thing this guy noticed was the most cylinder wear was in the small compact diesel tractors,or he called them task tractors that were ran a hour or less each day.The big engines that ran hour after hour or sometimes days at a time, the cylinders looked almost new. He did some investigating on starting a cold diesel engine,what he found is when a diesel is warming up there is a "danger zone" that a diesel goes through.I am not exact on temps, but he said around 110-160 deg, diesel fuel forms a acid which will slowly etch your cylinder walls. He suggested some warm-up tips for diesel owners. Make sure your thermostats are working properly, cold climates plug your block heater in, try to get through the "danger zone" as fast but safely as you can{fast warm-up do not let it idle long when cold). Do your oil samples, a nd change oil often if you do alot of cold running.

[jbplock]

Here is another article on extended diesel idling that complements info in the article quoted by 02Red Dmax ...

Fleet Watch: Idling Trucks No. 1 Waste (http://www.fleetwatch.co.za/magazines/Jul2005/61-IdlingTrucks.htm)

smile.gif

[Jim Brzozowski]

carco, I remember reading an SAE report based on a Ford Motor Co. study when they also determined that 90% of the wear on the engine comes in the first few minutes of operation. There was a graph showing the temperature vs wear. Really told the story. Once one is up to operating temperature wear almost can't be measured in the time frame they did their experiment.
02Red Dmax regarding your remarks on quick warm up. I couldn't agree more. Regardless of temperature, I always after a couple of minutes getting going I bring the rpm's up to 1600 and just hold my foot on the petal at that position. The allison will make all the shifts and until the torque converter locks up I just hold the 1600. Thats the fastest warm up that I consider safe for the engine. Some guys just jump in their trucks, drive 1/4 mile to the highway and stand on it, the tach goes up to 3000 between shifts and are up to 70 mph or more in no time. The temp gauge hasn't moved yet. That can't be good for the engine. The first few minutes are the most critical for wear, a lot of folks don't understand the difference in coefficients of expansion between aluminum and steel. Its a major difference and until the engine has reached full operating temperature I for one can't stand loading it real heavy by standing on the go petal. Once its warmed up, you really can't hurt it unless of course something is not right.