What Constitutes Excess Idling?

[elkhartjim]

I see and hear about excessive idling not being good, can y'all be a little more specific, what is excessive idling? 

I usually let my ISL idle for 2-4 minutes when pulling in to a rest area or at the campground check in stop. In the mornings it will take up to 2 minutes to air up depending on the pressures in the tanks. I sometimes will idle longer when sitting in the fuel line at a truck stop.

What say you, Joe?

[jleamont]

Jim, 2-4 minutes is not excessive by any means. On a cold start I will idle at low idle until my coolant reaches 100 degrees, then on goes the cruise control. (I will flip my block heater on below 50 degrees ambient 2 hours before we are set to leave). Cool down, I watch the Pyrometer, sometimes its 2 minutes other times its 4 (give or take) depending on how hot outside and how hard I was pushing it before we stopped.

[wildebill308]

Jim,  I feel the place where it can cause the most damage and be damaging to your engine is on start up. The big problem is your diesel won't warm up at low idle. I have made it a practice to go to fast idle as soon as I have good oil pressure on the gage + 10-15 sec ( I want to be shure I have good oil pressure at the turbo). The problem is at low idle your engine is not burning all the fuel. You can have problems with fuel washing down the cylinder walls and contaminating the oil. Fast idle produces a little boost and will do a better job of burning all the fuel.

When shutting down  I watch the EGT gage and let it get down to around 425 deg. before I shut down. The time this takes has lots of variables. from how hot it is out to were you climbing a hill when you pulled into the rest area/campground. I don't think you will have problems with fuel washing down the cylinder walls because it is at operating temperature. The cool down is more to protect the turbo so once your EGT's drop you should be good. The problem with shutting it down when the EGT's at high is it can "coak" (think burn) the oil in the turbo and plug the oil passages. Protecting the turbo is one reason I run a synthetic oil like Shell Rotella T-6.

Bill

 

 

[manholt]

Jim S.

At a Campground, I let mine idle while I check in, then it will do the same as I hook up electric.  Then, I will shut it off about 350 degrees.  In the morning I will do as Joe does and let it idle on CC while I unhook and get ready to leave...it will still be another 2-3 minutes before turbo fully kicks in, so be carful when merging into traffic!  If I get into a construction area that is a one way wait.  After a couple of minutes of sitting there, I will shut it down! 

[elkhartjim]

I do pretty much as Bill does on startup but I hadn't thought about waiting until the water temp gets to 100 before increasing to high idle with the cruise control. I don't have the ability to monitor my EGT temp, only water. I let the water temp drop to 185 during the hotter weather and depending on the ambient temp and the pushng it's been doing that can take up to 3-4 minutes I suppose. My concern has always been coking the turbo at shutdown.

Thanks guys for the information. 

[wildebill308]

I think a quality EGT gage is a good investment as EGT temps react much quicker than your water tempetures. 

Bill

[jleamont]

I have never been a fan of revving up a cold engine, especially if it's mine 

[wildebill308]

I agree, revving a cold engine is not a good thing. I do find that by the time you get ready, air bags up and idle out of the camp ground it is warm enough. I still go easy on the wide open throttle till it is completely warm.

"it will still be another 2-3 minutes before turbo fully kicks in, so be carful when merging into traffic!" 

Carl, Not understanding as my turbo will produce boost from start up if the RPM is over idle. 

Bill