Idle/Warmup time?

[Rattler]

If my old mind remembers correctly, the official word from Cummins used to be that our engines should never idle for more than 20 minutes. The main reason was that because our engines rely on heat and compression to burn the fuel, that at cold temps an excess amount of fuel is left unburned and ends up the the crankcase. Randy

 

[JGrefenstette]

huh, thats very interesting and good to know. becuase during the summer when its up around a 100* out in the evening, if i pull into a parking lot to talk with some buddies after running the truck hot, it takes for ever to cool down, so ill occasionally just let her run and run while we sit around an talk.

 

[cojhl2]

Now I don't condone idling long or often, but I will not put a tractor, a semi, a dozer, or even a gas engine to work until everything is warmed up. The trucking industry is in for many changes, when it comes to idling. I do know though if its below freezing, my service truck will not shut off until I'm home, if I have to work outside. I'm not going to be stranded, and I'm going to have a place to climb in and get warm if I need to

While I was living in IA my neighbor was an OTR driver. He usually came home to stay during the Christmas to New Year peiod.



One winter it was so cold that whole time, never above 0, he left his engine run the whole time. Once a day we would go up to the truck stop and take the engine to 2000RPM for about 5 minutes to blow the soot out.



Then we always stopped for a few beers on the way home.



When it's cold like that the radiator should be completely shutdown for air as the engine cools itself ingesting cold combustion air.

 

[JGrefenstette]

my moms dad, now 88 years old, once worked at a naval base in Alaska. he tells stories about locking the steering wheels on the loaders and other big equipment and running them in circles all night long, because the would freeze to the ground otherwise. or it might have been that the wheel bearings and the track dozers would freeze up. not sure. and the motors never got shut off. otherwise the freeze caps would blow i suppose and at temperatures that low.

 

[Forrest Nearing]

huh, thats very interesting and good to know. becuase during the summer when its up around a 100* out in the evening, if i pull into a parking lot to talk with some buddies after running the truck hot, it takes for ever to cool down, so ill occasionally just let her run and run while we sit around an talk.

doesn't hurt NEARLY as much to idle at 180* as it does at 20*!



idling hot in the summer w/ the A/C on isn't THAT bad, but I'll still see a little haze out the pipe if I do it for very long

 

[KOG]

Headgaskets on a Rabbit aren't quite the same. Those have aluminum heads which expand when warm. Gas engines with aluminum heads also have problems if run hard before warm.

It's not good to run any engine at full power before it's warm. But it's as bad or worse to let it idle when cold. Best thing for it is to crank it and drive away at a moderate speed. No, don't take it out cold with your 20T gooseneck and fullthrottle it instantly. But don't leave it idling either, warm it up as quickly as you reasonably can and keep it that way.

Alaska is a different situation, we don't live there. And we don't plan to replace engines every couple of years as a result either.

People who run OTR tractors have been learning, slowly in some cases, that it's not good to leave the engine idling for long periods.

 

[Forrest Nearing]

if we did live in Alaska, I would hope we would be smart enough to put an exhaust brake and a high idle cable on our trucks so that they could maintain a healthy EGT level while idling

 

[JLEONARD]

But it's as bad or worse to let it idle when cold

You'll never convince me of that... . that it's worse... . extreme cold being the exception of course.

While I drive mine easy at first, I certainly do not keep it below 10 psi boost in all cases. Sometimes when I need to get on the entrance ramp... . well I does what I have to.

My opinion of a warm emgine is 130/140 degrees... . that is the design temperature and everything should be at proper clearances at that point. That is engineering based.

For me that's when the needle on the temp gage gets past the first line.

But whatever makes you feel good... . that should be your plan.

 

[BradG]

i live in southern vt and plow with my 93 and i go as soon as i have oil pressure. i havn't plugged it in yet this year but we havn't dropped beelow -10. i just don't work it till it reaches temp and don't shut down till egts around 300 just like my old mack i drive at work.

 

[rumblefish]

Some days I just start my truck and let it idle in the driveway.

I have yet to own a diesel/auto combo, so tell me if I have got this right-



1. Start truck

2. Put in neutral

3. Admire custom body work thanks to a tree



:-laf

 

[McCRam]

I'll be idleing my truck longer when it is cold from now on. I have always believed that idleing is bad, and still do. But, I park about fifty feet from the highway. I travel about five miles before the temp gauge budges. Well the headgasket popped the other day. I thought I let it idle a long time, 5 minutes, never saw more than 10 psi. twenty miles later the heater startes blowing cold. Due to icy roads, This truck hasn't seen more than 20 psi for three weeks. So I am blaming this gasket on the cold. From now on It gets plugged in and idled for a few minutes before I get on the highway. Idleing can't be worse than coolant in the oil.

 

[tugboatphil]

I have yet to own a diesel/auto combo, so tell me if I have got this right-

1. Start truck
2. Put in neutral
3. Admire custom body work thanks to a tree

:-laf

I just about choked laughing at that! also add:

4. Make sure chock is of sturdier material than plastic!! :-laf

 

["Mad Max"]

Winter or summer, I fire it up and drop it in neutral, and let it idle for as long as it takes to get my coffee pored and get my jacket, kiss my wife goodbye, etc, and then get in and get going. When cold I'm more concerned about the transmission getting fluid circulated than the engine getting warm... and the transmission fluid won't circulate in 'P' either, have to drop in neutral. Plus, in my case, I have removed the heat exchanger (which is designed to warm up the transmission when it's cold outside) in lieu of the monster downpipe, so I let the transmission circulate for at least a minute. I'm dropping in a 6-speed this year so I'm not too worried about grenading the transmission so long as I treat it right.

Out here in 20* Colorado it takes about 10 minutes of cruising to get any heat out the vents. The hotter the engine gets the faster I accellerate.

When it's already hot, fire up, check oil pressure, and go.

- M2

 

[hdm48]

my first gen would take about 15 minutes to start to warm up, this second gen takes all day so I leave it plugged in.

 

[JGrefenstette]

i gotta say there are a LOT of interesting and good ideas about this. as said before though, i still think its almost necesary to let it idle just past the first line on the temp gauge, because unlike some of you who have nice back roads to putt-along while it warms up, some days i have to drive less than a mile before im on the highway. and its hard to explain to tailgaters why it takes you 5 minutes to get to 60mph and why your dumping white clouds out the back. if i let my truck spend a little more time (10-15min) at idle, it makes for a much more pleasant drive.

 

[91W350]

I am kind of late answering, but as soon as the oil light goes out, I am hunting a gear to get moving. I drive it fairly easy until I see temp needle movement. Not that it matters much in the 93, it would not work very hard wide open. I think it needs a few pump adjustments. I just drive it like a car though. It never pulls anything heavier than 3000 pounds and that it rare. It does fair on fuel, gets around 20 mpg most of the time, 18 or so at 80. It starts good, always quickly, sounds great and does not make much smoke at anytime. I never plug it in and it will start easily below zero. I think it is set very conservatively, the turning of a few screws would probably make it a lot more fun to drive... . I tell my friends it will do zero to sixty in two minutes. :-laf Glen