Leave the engine running

[mshirley]

A question from a new subscriber... ... I've read throughout this forum that one should only idle for short periods i. e. no more than 5-10 minutes. I've also heard that it's better to let a diesel idle for long periods as one just washes the cylinders down with fuel everytime it's started and some of that fuel just ends up in the engine pan where the sulpher can do more damage. (can turn into sulphuric acid??) Why do you see truckers leave the rigs running at truck stops?

Is there a definitive answer to this?

Cheers, Mike

 

[dpuckett]

Yes and no. THe washdown occurs when the combustion temperatures drop low enough (i. e. extended idling) that combustion is incomplete, thereby not only washing down your cylinders, but also clogging and varnishing your injector tips. The reason so many truckers leave their engines running overnight is: A) their grandpas did it, so it is good enuff for them. But, diesel starting and operating technology has come a LOOONG way in 40 years. B) It is better to burn a little fuel (or is it?) than to cook or freeze in the sleeper. More companies are installing ESPAR type heaterrs to run an AC/ heater, but many still rely on the engine to make the heat/ cool.



You shouldnt normally get any washdown when you start the engine. ANy that you do get should be VERY minimal. ANd, dont let it idle for 30 minutes in the winter morning to "warm up. " It will never get over 100 deg water temp if it idles all day. I just let the oil pressure get up,. maybe let it go another 30sec, then ease into it till the temp gauge gets to the first tick mark (next to the "C", not the first in the sweep), then go as normal. Diesels are designed to work or be off. Now, when refuelling, or going into the C-store for a pop, I'll leave it running. Less than 5 min, leave it on; more than that, turn it off.

AND... . ATF is NOT a good injector cleaner, Ford does NOT own Cummins. ANy other truck stop myths I missed that this newby should know about?

Welcome to the TDR, mshirley. Get ready to take out a second mortgage or get a second job to pay for the sickness for which there is no cure- the BOMBing bug. Stands for Better Off Modified, Baby. TReatment includes spending of ANY excess money you may have, many transmission, driveline upgrades, dyno runs, new tires more often, as rubber seems to get left on the road a lot as the bug worsens.



Daniel

 

[hdm48]

Well, there is a couple things.

When you see those trucks "idling" at truck stops, the ones that are there for a cup of coffee may let them idle for a couple minutes, then they leave. If the driver is going to spend the time sleeping, he will raise the idle to about 1100rpm for a cat, and 1500rpm for a cummins. This is insure cylinder temps stay in the safe zone and for proper oiling. But this is normally done during hot summers and cold winters for comfort. I know, I have driven for over 1,000,000 miles.

Now some states have posted laws that limit how long a truck can idle, even at a truck stop. In this case, I would just drive to the next state to get a good nights sleep. 'Cause at -40 degrees or +100 degrees it gets pretty ugly in that sleeper. Not to mention that at -40 you can blow the end right off a starter trying to start it up.

But in my truck, I let it warm up about 5 minutes if it is cold and about 2 minutes when it is warm just to insure everything is getting oiled.





Dave

 

[Greenleaf]

OkyDoke

My school buses idle a few hours each day and NEVER get a bad oil sample back yet after 10 to 15k miles on the oil.



My pickup engine will idle a lot and I don't care. Farm tractors a ton too.



My . 02



Scott

 

[JLEONARD]

I normally don't idle mine for very long, nor do I let it idle for warmming up. My normal start-up routine is let it idle in neutral till the oil P starts to indicate, then I idle out of my 100+ ft driveway in 2nd gear. Then it's all downhill or level city streets for about 3 to 4 minutes, then the expressway. I'm normally doing about 70 as I merge into traffic ... if there happens to be any.

I do idle at times for more than 5 minutes... I don't like to, but I do when necessary and I don't worry about it..... the coolant stays up to temp once the truck is warm.

I figure if I shorten the engine's life to 900,000 miles, or 800,000 miles ... . well, who would know anyway? The rest of the truck will be long gone.

That's another $. 02 from a realist.

Jay

 

[1stgen4evr]

Idling

I definitely idle sometimes. Once in Virginia when I stoped for fuel and shut off the engine, when I tried to restart, smoke filled the engine compartment as some of the wireing roasted itself. 600 dollars and half a day later, I was on my way. If I am fueling, the further I get away from home the more likely I am to idle.



If it is really hot I idle unless I am leaving the truck for the day as my wife travels with me and usually wants to be comfortable whatever the outside temp is. If the outside temp is really hot I will raise the hood because of having the overpressure relief valve blow out most of the refrigerant on one occasion.



I don't sleep in the truck so I don't idle all night. If I did I would. Near as I can tell, it has not hurt the Cummins. I run up 10k fairly quickly and change the oil on that interval. Have 390k on the 93 D350 with getrag. Uses no oil, cranks instantly and I feel confident to go wherever there is a paved road fully expecting to get back home.



1stgen4evr

James

 

[WadePatton]

Welcome aboard.



Now having read a couple hundred "idling" posts in a few dozen "idling" threads, I'll boil all that down and taint it with my Opinion.



The 24v's idle cooler and are more likely to have extended idle-related problems.



Higher-speed idling seems to overcome all the "low temp combustion" issues with both engines.



For 20-odd bucks you can buy a "throttle depressor" from Geno's and idle at any speed you like. Works on any engine. I let the engine run for a minute, then put the rod on and dial it up to 1000-1200 (watching the EGT's helps).



I plug in and high-idle for warmup in cold weather. I idle lots in the summertime to keep the A/C blowing on the dog. Popping hood is a good idea. The OEM fan doesn't always pull enough air for the A/C. 10-15 minutes is probably the longest of my idles.



If idling kills it---well we'll never know, my fuelish behavior will APPEAR to be the culprit. :-laf

 

[BushWakr - RIP]

** DARN**... . Idle ..... can you describe that for me..... I'm from the nascar mark school of diesel technology... . it's either "OFF" or "MAT THE SUCKER... " OR ". . YA YA THE NEEDLE WILL STOP GOING UP WHEN IT GETS TO 1800*F, DON'T DISTRACT ME WE'RE DOING GOOD... " ... . Now pass the sacremental wine will ya... .



Pastor Bob... .

 

[hdm48]

Sounds to me like you've had enough of that there wine, bubba.











Dave

 

[JLEONARD]

Another point... . if excessive idling will kill it, then why are there traffic jams?

Are traffic jams really a governmental plot to kill all diesels?

OK Pastor Bob, I'm passin' the bottle back your way!





Jay

 

[Greenleaf]

Hmmmmmmmmmm

... ... ... ... . the plot thickens... ... ... ...

 

[MrWinkey]

I have cousins who drove long haul/log trucks for years w/ cummins motors in them.



They said the main things to watch out for are... ... .



1. Watch the EGT's... ... easy to get too hot when pulling a big load of soon to be paper up a pass in 110 deg heat. They said BADDD DEAL

2. Check your coolant. They told me they put cyl's in 2 of their trucks @ only ~600,000 miles as they did not check the coolant enough and got pinholes in the sleves from the coolant.

3. Dont lug it. I asked why they just said "Dont"



BTW they never let one truck get cold for 9 months. Infact they told me they never shut it off except for maintence.



If I make it 600k on my truck that's fine w/ me. Heck there probably will be enough other problems I'll have to rebuild everything by then!

 

[JLEONARD]

2. Check your coolant. They told me they put cyl's in 2 of their trucks @ only ~600,000 miles as they did not check the coolant enough and got pinholes in the sleves from the coolant.

Well since we don't have sleeved engines that's ONE less worry

Thank goodness for "parent bore" engines.

Jay

 

[cerberusiam]

my fuelish behavior will APPEAR to be the culprit

Yeah, yeah, thats the one!