I read in my friend's tractor manual (he has a farm tractor with 3 cylinder direct-injection engine) that excessive idling is bad for the engine because it keeps the engine temp too low.
I often let my truck idle for 15-20 minutes and occasionally for an hour, but whenever i come back the engine temp is still between 180-190 F so i wonder if this fact applies my my situation as well?
Plus i see the big rigs idling all the time, although i know they are much different.
Can anyone explain a bit more about this, like how much idling is too much and how bad is it?
thanks,
Paul

its interesting, because I had similar questions on this exact topic. How much fuel does the 6.2 use idling, roughly? I have heard 'urban legends' that it takes more fuel to start a diesel then to let it idle for 15 minutes or so... and that its better to let it idle. Any opinions on this?

If you listen carefully at a truck stop, you'll see that very few operators let their trucks "dead" idle. They high-idle to eliminate "wet-stacking," the condition that occurs because diesels don't build much heat at idle.

At least that's how my pea brain comprehends the whole situation.

Excessive idling is bad for all diesels, even big rigs. Unfortunately sometimes when it is very cold out the engine has to be left idling or it won't restart. Idling basically doesn't keep combustion temps high enough for complete fuel burn and cylinder washing can take place along with fuel getting past the rings and into the crankcase oil. Excessive idling can also cause build up on injector tips. Good rule of thumb, try not to idle much more than 15 to 20 minutes at a time if possible. If extended idle time is unavoidable, change your oil more often.:eek:

If you leave your truck idling for an hour and your coolant temp is still well within operating range, then your not doing anything any harm.

My 6.2 truck was more likely to overheat than get too cool while idling... but that was partially due to the rad fan sitting behind the back seat....

Startup and Warmup are hardest on diesel engines, much harsher than idling.

The worst thing that can happen from 'excessive idling', is a little bit of carbon buildup that you can blow out with that pedal under your right foot.

Tex,

is that a gun you are holding in your picture?
Paul

M4 Carbine w/ M68 Sight
'Army Toys'

M4 Carbine w/ M68 Sight
'Army Toys'

I always liked the comp-m. the new holosights are even better, though im not sure as durable. m4 was great, especially the m4a1. nice high n tight by the way. i didnt know the canadian army made you guys wear that dumb haircut..unless youre not? fill us in

D.CARMILLERI is dead on. All idleing is hard on any diesel for the reasons he states. As for start-up being a lot harder on the engine than ideling, I don't believe all start-ups are the same. When and engine has had a short period of shutdown, a couple hours, there is still plenty of oil on the bearings. After several hours when the engine has cooled off and more oil has run off and more oil has been forced out due to tighter clearences, that's a different start-up. I consider idleing about the hardest hours put on a diesel. It wastes a lot fuel, washes cylinder walls, thins the oil and builds carbon. Just my opnion, based on a few decades of operating diesels. PMB

I agree, Slomoe, if you have a good electrical system, (starter, cables, batteries, connections, glo-plugs, alternator, etc.) use a good grade of lubricant/engine oil and everything else is equal, there is no reason to leave an engine idling. I turn mine off and restart it when I'm ready to go.

In this day of high oil/fuel prices, it's a waste of money and resources to leave it running when you are not moving. You are not only getting zero miles to the gallon while idling, but you are using up the oil and the engine parts as well. If the engine is running, it's wearing out!!

I didnt know the canadian army made you guys wear that dumb haircut..unless youre not? fill us in
I should have specified, US Army, note screen name.

I should have specified, US Army, note screen name.

I did note it. I also noted your location as being Ontario, Canada. Hence the reason I asked.


Back on subject, New Jersey passed a law recently that its illegal, and fines are given out, for drivers of diesel vechicles that are idling for 3 minutes or more. There are exceptions but it is limited. There are signs at all the convience stores. In fact, you can buy your own sign. http://www.state.nj.us/dep/stopthesoot/sts-no-idle-sign.htm

Here are some quotes from the site:
2. How long am I allowed to idle to warm up my diesel engine?
A motor vehicle may idle for 15 consecutive minutes when the vehicle has been stopped for 3 or more hours. However, most diesel engines take 3 minutes or less to warm up (consult the engine manufacturer’s recommendations). Limiting idling will save gas and money.
16. Wouldn't the continual shutting off and turning on of diesel engines actually damage the engine and emit more soot than idling?
Idling an engine for more than about 10 seconds actually uses more fuel than if the engine had been turned off. It is more efficient to turn an engine off if it will be stopped for more than 10 seconds. Frequent restarts of an engine will not have a negative impact on engine components (7).
17. Isn't it bad to drive a cold engine if it hasn't been warmed up?Electronically controlled engines need no more than about 30 seconds to warm up. Driving a vehicle cuts warm-up times in half. The best way to warm up an engine is by driving it, while avoiding rapid acceleration and high speeds for approximately the first four miles in cold weather. (7

http://www.state.nj.us/dep/stopthesoot/sts-faq.htm#2

here's a twist... my 6.2 comes with an advance switch that lets the truck idle either A) richer or B) other. I'm not sure exactly how it works but I know that I can walk out to my truck any morning, crank it over and flip the switch, walk back inside and finish getting ready and walk back out and it's ready to go. I wish I could tell you what rpm it was running at, but it's definitely different from a straight idle, and whenever I come back out 20-30 minutes later, it's running at about normal running temp. Is this idling bad for my engine???

Sounds like someone wired the switch to fault the cold advance idle. good idea actually.

at least on my truck, low "normal" idle is 600rpm, while the fast idle is 800 rpm. as per stated on the emissions tag on top of the radiator support.