Idling times for cool down

[Minn-kota]

I read an interesting paragraph on Banks website about how idling to cooldown a diesel is not necessary and basically a waste of time.

What are your thoughts on this? I tend to idle a little bit after a drive but nothing excessive. Is it necessary with today's diesels?

:confused:

[dayle1]

I'd like to add to the question. If ideling is important, how do you handle fuel stops? First your pulling a load at 70 mph on the interstate and 30 sec later, you are at the fuel pump.

[hoot]

I don't shut down when I refuel. Diesel fuel isn't as volatile as gasoline and diesel engines don't have high energy spark ignition.

Doesn't mean what I do is right.... but that's what I do.

[a64pilot]

I do like hoot. As far as not being necessary, maybe maybe not. I go with even if it's not necessary, it can't hurt. But then again I idle anything that I run hard for a short period prior to shutdown, yes even the lawnmower. Emphasis on run hard, I don't believe it's necessary unless you have elevated the EGT's and held them high for a while. Of course I've never worn out an engine either and I've driven plain gas motors over 250,000 miles. The rest of the vehicle always wears out on me and I get a new one based on the body , suspension , accesories etc. being wore out. I assume I'm doing something right.

[AlanL]

I do the same thing when I'm towing... leave the truck idling when fueling, even when I stop for lunch if I've been driving up and down hilly terrain for the past couple of hours.

The remote starter is good for this. I can have the truck running, then trigger the "stay running" feature and remove the keys. This means that I can use the rest room, wash the diesel off my hands, etc... and not worry that someone is stealing my truck or the stuff inside it. If I stop for lunch and have triggered the "stay running" feature, it will even shut itself off after about 20 minutes.

As the original poster said, its probably unnecessary, but I do it anyway.

-Al

[Idle_Chatter]

I know there's a lot of plus and minus on this topic, and if you feel comfortable with doing a cooldown there's really no downside to it. I personally feel that the design of our turbos and the EGT numbers that I've been watching on my truck don't make it really necessary. I just got back recently from a week in Kansas pulling my 6x12 cargo box with at least 2,000# on board in 90+ degree heat running interstate and AC on max. My EGTs stayed mostly in the 900-1000 degree range running 65/70. Taking an off-ramp for a fuel stop, they would almost immediately drop to the 300-400 degree range at idle. I never did get off the interstate, into a fuel dock and stopped in "30 seconds" more like 2 or 3 minutes. When I was finally docked and ready to shut down, my EGTs had been 300 degrees for some time. Even coming off an 8-hour run at 900 degrees, I feel that a couple of minutes at 300 degrees is plenty of cooldown. I always shut down. I pop the hood, add fuel treatment and fill the tank, clean the windshield and lights, do a walk-around and check the tires and trailer and then open the hood, look at belts/wires/fluids and check the oil before buttoning up and going in to pay. Bottom line is to do what you feel comfortable with, because it is your truck. smile.gif

[hoot]

The good news is you almost never hear of problems with turbo's on these trucks.

[Amianthus]

Here's my take on this. I usually let it idle down to 300F (pre-turbo) and then shut it down. This varies based on how I just ran the truck. before it shut down (I have a temperature controlled shut-down device). My times vary from one minute to 8 minutes, depending on the run.
If you do not have a pyro, a good rule of thumb is this. Take the last speed you traveled at for longer than 10 minutes. Divide that by ten, and then cut that in half to get minutes of idle time. EG- 70 mph, then 7, then 3.5 minutes of idle. 30mph, then 3, then 1.5 minutes. It's not super-scientific, but it gets you close.
Just my thoughts.

[GMCTRUCK]

The cooling down period has nothing to do with being a diesel. It is for the benefit of your turbo, mainly the shaft and oil passages. Oil left to boil on a hot enough surface can "coke" which basically is a burning up and drying process. It can eventually build up enough to cause problems. Being water cooled our turbos cool down pretty fast. I usually wait until 230 pre turbo but, like I said it gets that cool very quickly with our turbos so no big deal.

[tysmith]

Ditto what GMCTRUCK said. The cool down is very important for non-water-cooled turbos. The garrett turbos in my diesel Volvo's get quite roasty, so I let them cool for a few so as not to coke 'em. Water-cooled is much safer...

Ty

[peachin]

So when you are in Park with the engine running - for sometime - isn't the Transmission heating up.
Is the transmission only cooling when the tranny is engaged in forward gears?

An aside: don't you love it - when you see a big
diesel dooley - sittin" and running while the owner is getting his cigarettes, donuts and coffee
and the remaining BS - this idle thing - I think is a very cold weather thing - unless someone wants to change my mind - I'm always full of mis-information - tune me up!

[jesshd]

The newer IHI and Garrett type turbos are water cooled. Coking is a thing of the past. Also, synthetic oils do not coke. Just stay out of boost for the last couple of miles before you park and shut it off. The coking and idle to cool down was back when people were not running synthetics and the center sections of the turbo were not water cooled.

Jess

[needbigtruck]

My $.02 worth. I let mine idle after a hard pull to cool the turbo, but more important to me at least is to let the entire engine cool down and reach the same temperature. I read somewhere here, early on, that doing this may help to preserve our notorius head gaskets. In other words letting the iron block and aluminum head all reach the same temperature may help prevent warping and hence a head gasket leak.

[a64pilot]

Peachin,
Not sure about the Ally, but all other tranny's that I can think of pump oil through the cooler whenever the Tq. converter is turning, I.E. engine running. They don't if the engine isn't running though, it's for this reason I believe that you shouldn't tow an auto equipped vehicle with the drive wheels on the ground.

[Gbenzx01]

Banks said what?
You mean the Banks that markets every sort of thing connected to highest temps on a truck?
Now if Edge Products said it I would think nothing of it.
Could be, as busy as they are could be a waste of time for who, Banks.
But for the rest of us?

Thanx Gben