With the 2005 Dodge Cummins is it necessary to idle the motor after driving around town or on the flat highway with no load? When turbo cooling is needed (whenever that is, such as towing) how long should I idle the motor? Does the time on the exit ramp, at the stop sign and 35mph driving before destination count toward the idling time? Thank you.

 

I really don't have an answer for you, just reference for my '01. I needed to instal my Pyrometer gauge before I really knew how long it took to cool down. General consensus is less than 400 deg F, with a preference to 350 deg F or cooler. Reasoning being the upper breakdown temperature for the motor oil used to lubricate the bearing. Too hot and it cooks down to carbon sludge, restricting flow and possibly burning up your bearing/shaft. Other thoughts are that it isn't an isuue, hasn't been a problem on many trucks to shut her down after roaring down the interstate towing 20k pounds for 100k+ miles. I got the Pyro, mounted it pre-turbo in the exhaust manifold, and take some time to cool down when I stop. Sometimes the off ramp coast and 35 mph drive work to get things cooled, but not always. Mine cools down much faster if I shut off the A/C early so the condensor can cool down for awhile. Hope this helped you out some...

 

WIth my rig

which is a 12V i have the post turbo set up, i bought it that way, i simply add 300 degrees to whatever the reading maybe, my egts, at about 300 max on the pyro when im idling, so i have no basis of when to turn it off, but i assume if its been idling a couple minutes or so and its steady at 300 degrees, i go ahead and shut her off.. Hope this helps..


PS welcome to DTR Fred!

Tx

 

I myself don't know what to think.... the owners manual reccomends cool down times, but Banks says not necessary for turbo diesels http://www.bankspower.com/tech_TD-fact-Fiction.cfm i have gotten into the habit of listening to one song on the radio /CD player before shutting down..... I will do that until gauges are in

 

From what I have understood, letting it idle OUT OF GEAR does help before you shut it down. For the little bit of difference that it does make, it's not overly necessary BUT really, for a minute or two of your time, it couldn't hurt. I will say though, some do look at me funny when I'm sitting there idling it. They'll come over and ask 'Why dont you shut that noisy thing off?' I just grin and say 'WHAT?'

 

Noise? what noise.... I dont hear anything

 

OK everybody lets refresh this again, the turbo charger has 2 funny looking wheels on either end of a small diameter shaft. One side has an impeller that pushes fresh air into the engine and the other side is driven by the HOT exhaust. In a distance less than 12" the little shaft supports these 2 impellers and turns as fast as 130,000 rpm which is fed oil by the engine oil pump and is returned directly to the oil pan. Any compressor generates heat and the exhaust is a source of heat cooled by oil from the engine which unless it is synthetic will start to decompose from excess heat (268F). When you shut the engine off there is no cool oil running through the bearings and the components are subject to heat soaking in other words the hot exhaust side will start to transfer heat to the shaft first and then the rest of the turbo components all of which is mounted to the hot exhaust manifold. The oil if too hot 300F+ will start to "COKE" or turn into a black hard tar like substance which will eventually stop the the oil from going through the little hole which feeds oil to the bearings cooling and lubricating the bearings. Now your turbo is lacking lubrication and the engine is trying to push the impeller and getting hot which either seizes the shaft causing lack of power black smoke or the shaft will twist off causing other residual problems. Banks is right under the condition where a cool down system is installed either by a timer which idles the engine for you or supplies oil to the turbo from a pressurised system after the engine has been shut off. The harder an engine is worked the more residual heat to dissipate from the components. This whole process could happen in a few hours of poor operator awareness under extreme conditions or over weeks of bad habits and impatience. V8's are more prone to this as the turbo is usually mounted in the back up on top of the engine where heat dissipates slower but I6 engines will coke turbos with poor judgement just as easily. PK

 

Your owners manual explains shut down time after use. I've read it myself, so I can say it is in there..