Question for diesel owners

[Rob_M]

Originally Posted by Dr. Mike

hello all
There is a lot of great lessons and conversation here. But, I do have a few questions that were not addressed in four pages of posts.
1- Can someone define "modern" diesel?
2- I understand about the excessive idle, but is there any rule for being stuck in bumper to bumper traffic for hours?

Best
Dr. Mike

No expert, but I would define “modern” as post-emissions with computerized injectors. Idling a pre-emissions diesel won’t hurt it. Contrarily, anything with an exhaust particulate filter does better at high idle and up to keep from clogging it up. A parked regen requires high-idle or above. I also believe an EGR system is better off not idling forever.

My experience is 30+ years driving medium duty diesel heavy equipment service trucks which use basically the same power that DP’s use. My current work truck is a 2019 Pete with an 8.9L Cummins. Basically my daily driver as it goes home with me.

[Unplanned Tourist]

Cummins, DD, Cat and IHC have advised against extended idle time since the early 90's.

Before then, well let's just say they didn't know better.

We had many customer's with what we called "slobber" showing at the various exhaust connections due to extended idle time. Caused by unburnt fuel coming out the exhaust ports.

If you must run a diesel engine for extended time, run it at a minimum of 1000 rpm.

[Unplanned Tourist]

I just read this on a Cummins news letter-

"We know I said earlier to idle your engine upon start up, but don’t idle your vehicle for to long. Prolonged idling is obviously bad for our environment, but it will bring your engine to an early demise. The prolonged idling causes insufficient lubrication on the piston wall which could lead to piston and cylinder block scoring. In ye oldie times, diesels were required to run constantly to prevent the fuel from gelling. However, now this is not the case so, if your taking advice from a stubborn old timer who’s telling you to idle your engine, politely ignore his advice."

Full article here.......

https://www.4btengines.com/how-to-ge...diesel-engine/

[NevadaNick]

My 1999 Cat backhoe said in the manual when cold to run full throttle and pull a lever so that the hydraulics went into bypass to get the temps to working conditions. Idle is just not needed except in extreme conditions of a hard pull to let the temps drop before shutoff. Normal operation just does not require it. If idling was necassary then UPS would not shut off their trucks, yet they do at every stop and the trucks last until they literally fall apart.

[Ray,IN]

Originally Posted by NevadaNick

My 1999 Cat backhoe said in the manual when cold to run full throttle and pull a lever so that the hydraulics went into bypass to get the temps to working conditions. Idle is just not needed except in extreme conditions of a hard pull to let the temps drop before shutoff. Normal operation just does not require it. If idling was necassary then UPS would not shut off their trucks, yet they do at every stop and the trucks last until they literally fall apart.

I would trust the UPS accountants before anyone else but engine mfgrs., they run the figures on engine rebuilds too.

[zzotte]

I know how annoying that can be, it’s really no reason to idle modern Diesel or gas engines for that matter with all the technology now in place, wastes fuel plus unnecessary pollution as if we don’t have enough, however it’s one reason: ignorance

Zzotte

[Rhitch54]

When you start a diesel in the morning you have to let it run to build up air pressure in the air tanks so you can operate the air brakes if you don’t it won’t move until then!!

[PeterFTH]

Your diesel will not suffer any stress if the first few miles (8-10?) are at moderate speeds. As you approach a freeway there should be at least some movement of the temperature gauge. You do NOT have to sit in your campsite and idle longer than it takes you to get underway.

[Clemson]

Originally Posted by Backcountry1

Most of the time it’s to warm up the engine, the engine oil, and the antifreeze/water temperature.

It’s not good for the engine to be put under stress/strain (especially when it’s needed to tow the trailer) when the engine is cold.

Same goes with letting it idle for a few minutes after running it hard. It allows the engine and components to cool down before turning it off.

Your comments are very true for the 1970s generation diesels. Prolonged idling in modern diesels is harmful to the engine.

[BJC FORZA]

I agree no need to warm the new gen diesels. The engine will warm up faster pulling its own weight and load out of the CG and onto secondary roads. Then I make it practice to accelerate to highway speed as easy as possible to get everything warm and functioning! Pro long idling is not good for any diesel.

[RTS]

With regards to my Cummins engines, it has been stated to get the temperature up to 140 degrees before putting a load on the engine. However, because of the large amount of cooling required because of the turbo, idling never gets to 140. So, I think the best way is to get the air up and slowly start your drive until you reach 140 degrees.

[SoCal3]

Nobody wants to hear a loud engine running, but consider this: Many DP's have air suspension and more importantly air brakes. I have to idle about 5 minutes to build the pressure enough to operate the brakes safely and get the suspension off the bottom of the air bags. Also, my unit has hydraulic slideouts so the engine has to be running to pull the slides in. So to all those saying it is totally old skool thinking just don't know what they are talking about.

[Drkruse]

Diesel pushers need to idle for some time to build up their air pressure for the air brakes and the air shocks

[jeepsrule]

Old school thinking. In a motorhome rally Cummins told us by the time your air brakes are up to pressure it’s time to roll. Then you idle out of a camp make a few turns and miles before you get on a ramp and accelerate onto the highway.