Engine/Transmission (1994 - 1998) Correct EGT for turning engine off?

[JHenry]

I have a hard time figuring out the search feature. I never seem to ask the right questions. Soooooo..... here goes.

A while back I followed a discussion about the correct temperature at which to shut off a 12 valve. It seems like it was around 3-4000? Can someone enlighten me? Thanks. JH

 

[WDixon27]

i shut mine down at 300* but with the manual transmission i can cool it down coasting though the lot in gear on the way to my spot and get it down faster, in the winter it almost doesn't need extra time to cool if i drive it right but the time goes up to a few minutes in our 100* temps with the ac running and my open BHAF sucking the hot air off the condenser/radiator

 

[GSchlegel]

I've always let mine get below 300*, try for 250*. I also let it sit for a couple minutes at idle so the turbo is spinning as slow as possible before shutting down and starving it of fresh oil. (It will continue to spool down for a while. )



Gene

 

[ctrlaltdl]

My EGT probe is pre-turbo and I can't seem to get mine below 350, so I usually only wait till it gets below 400. I figure if I shorten the life of my turbo it'll give me an excuse to upgrade. ;-)

 

[HBarlow]

When I joined TDR the common wisdom said allow it to cool to 300*. I followed that guideline. During one of the sessions during the big TDR Rally held at the Cummins Mid Range Engine Plant in July of 2002 when Dodge and Cummins introduced the new Gen III HPCR trucks and engines a Cummins engineer told me below 350* was good enough.

During a discussion here on TDR a few months ago a fellow TDR member reported that he had taken the time to watch his EGT gauge and the clock while allowing a cool down delay. He reported that if he followed the guidelines in the owner's manual suggesting a cool down between one and five minutes depending on whether the truck was driving around town unloaded or towing heavy on the interstate, one minute cool down time corresponded with 400* shut down temperatures.

Apparently 400* is sufficient for turbo protection.

Some Dodge-Cummins owners including our TDR Editor Robert Patton have reported that they ignore cooldown and shut their engines down like a gas motor with no cool down delay at all.

I always allow my EGT to cool to 400* or less but suspect that our engines and turbos are plenty robust to handle hot shutdowns after routine driving.

 

[BDaugherty]

On my '01, I have the Attitude set to shut down at 300*. It usually takes less than 30 seconds, even with temps in the 90s and A/C running. I think my PSM cold air kit makes a difference in that regard, however I have no scientific testing to back that up. It just makes me feel a little better to think that.

 

[JHenry]

Thanks to everyone for their comments. JH

 

[CumminsPower98]

I usually cool to between 350 and 400 pre turbo. I run synthetic oil so this helps keep any coking from occurring. I have had my turbo apart after hundreds of thousands of miles and it was perfectly clean inside.

 

[Woodenhead]

If you get it down to 350 for a minute or so it'll be fine. The way it was explained to me is that the oil starts to coke at 400F+ so if the EGTs are above 400 when it's shut down the oil that's sitting in the turbos bearing will coke up a bit. Too much of this and kiss the bearing in that little screamer goodby. Notice how if you get it to 400F without letting it stabilize, then shut it down and turn the key back on (engine not running) the pyro. starts climbing back up from the heat in the surrounding metal. This is the reason for letting it run while at 350F for a bit before shutting it down.



Mike