So what's the verdict?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

infernoredram

Senior Member
Joined
Feb 13, 2011
Posts
1,122
Reaction score
88
Location
South Texas
Ram Year
2007
Engine
5.9 Cummins
One of the most asked questions...diesel idling, good, neutral, or bad?

I have looked all over the interwebs and have not found a single straight up answer or any proof of what it does, if anything.

At my university, one of the bigger departments is agriculture, so you see a lot of diesel trucks around campus. Something I'm always seeing, are those guys in their trucks sleeping, or just waiting for a class. Are they hurting the trucks idling like that, or does really have no affect on the diesel?
 

Nickxxxr

Senior Member
Joined
May 15, 2011
Posts
798
Reaction score
1
Location
Near Reading, PA
Ram Year
2011
Engine
4.7
Don't have a real answer for you but my diesel service truck sits and idles at every call i go on for the compressor. About an hour to hour and a half probably six or seven times a day for ten years now. She is still running strong.

Sent from my SAMSUNG-SGH-I897 using Xparent Green Tapatalk
 

(S.M.R) 101

Senior Member
Joined
Apr 3, 2011
Posts
2,591
Reaction score
164
Location
Corning, NY
Ram Year
2013 Sport
Engine
5.7L HEMI
My work CTD stays on about 90% of the day on different sites.... but then again it's a 2012 with 5K on it so I have no idea if it's harmful or not.. not enough time with it
 

MADDOG

Not RamForum Staff
Supporting Member
Military
Joined
Dec 26, 2011
Posts
14,443
Reaction score
9,877
Location
Arizona
My contractor buddy runs 12 - 15 CTD's in his fleet. In the winter they idle all day. His only problem has been with the newer trucks and the DPF clogging up. Other than that, he has a couple of older 5.9's with over 200K on them and they are still going strong. They don't look all that great, though. ;)
 
OP
OP
infernoredram

infernoredram

Senior Member
Joined
Feb 13, 2011
Posts
1,122
Reaction score
88
Location
South Texas
Ram Year
2007
Engine
5.9 Cummins
Lol yeah I've heard it's bad to idle the DPFed trucks, but it's not bad on the 5.9...I've also heard that the fuel coats the cylinders though?
 

ramhunter9

Senior Member
Joined
Jun 25, 2010
Posts
24,464
Reaction score
974
Ram Year
2012
Engine
P-Star Jeep Wrangler
I let mine idle all the time .. even on cold days start ups I set her to hi idle mode
 

Stangshcky12

Senior Member
Joined
Oct 26, 2011
Posts
9,047
Reaction score
941
Location
Oshkosh, WI
Ram Year
2007
Engine
5.9 Cummins
I'm in the Ag dept at my university lol
Idling can cause dpf on the newer trucks but I don't think it does anything to pre -07
A big reason your here bad things is because of emmisions. With how many large trucks are idleing around the world at any given time its quite a bit
 

ramhunter9

Senior Member
Joined
Jun 25, 2010
Posts
24,464
Reaction score
974
Ram Year
2012
Engine
P-Star Jeep Wrangler
Emissions ... whats that ..LOL
 

Mopar1973Man

Senior Member
Joined
Aug 22, 2011
Posts
825
Reaction score
21
Location
New Meadows, Idaho
Ram Year
1996, 2002
Engine
1996 Dodge 1500 (V8-5.9L) & 2002 Dodge Ram 2500 (5.9L Cummins)
Last edited:
OP
OP
infernoredram

infernoredram

Senior Member
Joined
Feb 13, 2011
Posts
1,122
Reaction score
88
Location
South Texas
Ram Year
2007
Engine
5.9 Cummins
Great info Michael...that's exactly what I was looking for! Thanks for all the responses....now I just need the money to buy gauges to watch my EGTs..
 

Mopar1973Man

Senior Member
Joined
Aug 22, 2011
Posts
825
Reaction score
21
Location
New Meadows, Idaho
Ram Year
1996, 2002
Engine
1996 Dodge 1500 (V8-5.9L) & 2002 Dodge Ram 2500 (5.9L Cummins)
Like my comment about vehicle accidents I use to work for the local fire dept and have to get walking injured people off the highway into a warm pickup when weather was bad. So 6 cylinder high idle and my exhaust brake I could hold 500-600*F worth of EGT's and coolant temps would stay up with the heater rolling full bore. Then all my emgenecy lights too running...

accident.jpg


So while your looking at getting the pyrometer you might consider building a high idle kit for your truck too...(On for 98.5 to 02).
Mopar1973Man's Dodge Cummins Articles - High Idle Modification

Here is how it operates...
High Idle Operation - YouTube
 
OP
OP
infernoredram

infernoredram

Senior Member
Joined
Feb 13, 2011
Posts
1,122
Reaction score
88
Location
South Texas
Ram Year
2007
Engine
5.9 Cummins
So right now I'm idling in my truck waiting for class, and I have the high idle on. I got a few more questions...

1.) when do you need to actually use high idle? When you idle for 10min? 30min? 1hr? Etc..

2.). Does it hurt your idling fuel economy? (if there's such thing)

3.). My high idle is set at 1100 RPM, is that correct?

Btw...I live in south TX, so cold temps don't really exist. Its 84 right now
 

ramhunter9

Senior Member
Joined
Jun 25, 2010
Posts
24,464
Reaction score
974
Ram Year
2012
Engine
P-Star Jeep Wrangler
I only use high idle when the temps are cold . Helps heat the truck up better at first start up . After that I dont ever use it .
Why you would even use High Idle in Texas is beyond me ?

And yes 1100 is fine .
 

BlackedOutHemi

Senior Member
Joined
Feb 27, 2011
Posts
5,454
Reaction score
196
Location
DFW, Texas
Ram Year
2012 & 2012
Engine
5.7L HEMI & 6.7L Cummins
I only use high idle when the temps are cold . Helps heat the truck up better at first start up . After that I dont ever use it .
Why you would even use High Idle in Texas is beyond me ?

Well, it got down to freezing one night this winter. Lol. Mighta needed it then!
 

Stangshcky12

Senior Member
Joined
Oct 26, 2011
Posts
9,047
Reaction score
941
Location
Oshkosh, WI
Ram Year
2007
Engine
5.9 Cummins
At 84 youll be fine haha, the autmotatic high idle only functions when the IAT is below 32* or the coolant temp is below 175*
Your truck will be fine idling at normal rpms when its that warm and I doubt your going to be in the truck for more then 2 hours
 
OP
OP
infernoredram

infernoredram

Senior Member
Joined
Feb 13, 2011
Posts
1,122
Reaction score
88
Location
South Texas
Ram Year
2007
Engine
5.9 Cummins
Ooooooh lol. I was told to use it to
Prevent wetstacking(?)..unburnt fuel coating the cylinders and creating problems in the engine. I don't know if that was just cold weather though? Lol
 

WhiteExpress

Senior Member
Joined
Sep 8, 2011
Posts
18,185
Reaction score
3,275
Location
Midland, TX
Ram Year
2004
Engine
5.7 Hemi
I used to let my '95 idle for hours when it was BF cold outside. Maybe the 12Vs didn't have any issues with it. Truck always ran great, heater was always nice n warm.
 

Mopar1973Man

Senior Member
Joined
Aug 22, 2011
Posts
825
Reaction score
21
Location
New Meadows, Idaho
Ram Year
1996, 2002
Engine
1996 Dodge 1500 (V8-5.9L) & 2002 Dodge Ram 2500 (5.9L Cummins)
I used to let my '95 idle for hours when it was BF cold outside. Maybe the 12Vs didn't have any issues with it. Truck always ran great, heater was always nice n warm.

!2v's doesn't have this issues because the cylinder are slightly higher from the head configureation. Where the 24V tends to run cooler and this problem starts to turn up. Heck yesterday morning I started out at +6*F above and had a high temp of barely 33*F...
 
Top