The service manager at my dearlership told me it wasn't necessary to let idol for turbo cool down. He said the engine runs cooler than any of the other diesels out there. I'm talking stock, any thoughts?

I don't think anyone knows.

I have had to let my truck 'Idle Down' for 4 minutes once after a particularly long pull while towing.
Our turbo bearing is water and oil cooled which speeds cooldown, but a hot shutdown is not a good idea. Oil can oxidize or 'Coke' on the turboshaft under those conditions.

300F preturbo and 300F or lower post turbo for maximum longevity of turbo.
The biggest danger of a hot shutdown is the turbo is still spinning quite rapidly, and on shutdown you deny the turbo oil while it spins from XX,XXX RPMS down to 0 RPMS.

I take it back, good post GJ. BUT, on a summer day, i can't get under 400 sitting in the drive.

354-364 is all I can get on idle down

I wonder if that is common with the VGT turbos.... My friends 6.0 is the exact same way.

roughly 360F

Should be safe at that temp

Check out the information I found from Banks, specifically look at what they call Myth #7

http://www.bankspower.com/tech_TD-fact-Fiction.cfm

“Turbochargers haven’t used babbitt bearings for over 30 years, and today’s oils resist coking. Synthetic oils won’t coke, period.”

Personally I run synthetic oils in every part of my truck I can, funny thing I noticed since the change over from dino to synthetic oil I’ve noticed either my engine is just a bit quieter or my turbo is singing louder (possibly a little less friction = easier spool up due to synthetic?) dunno which but I like it.:ro)

Anyway enjoy the info from Banks in the link

Synthetic oils won’t coke, period.”


I know these aren't your words, but I don't think this is a true statement, although the temp is higher before coking occurs.

I appreciate all the replies. One more question for those that tow, has anyone seen egt's go high enough to have to back off the pedal? This is for those with or without tuners or chips.

You don't have to tow to see that.

Correct - We see high temps at higher altitudes all the time, towing or not, mods or not. For those of us over 5000', I think EGT is a must, because you can get into those temps in a hurry. a 4" exhaust helped about 100 degrees, but is not the solution.

I am in the process of designing a water injection system tailored to towing, actually will be a dual use system, towing and performance. See sig.

I have seen EGT's in the 1300 range w WOT and no trailer, put a trailer behind and it's a lot worse. I have to wait several minutes for my EGT's to get below 365 with normal driving. Synthetic oil has a flash point of ~ 470.

OK, now I know I need a gauge so what is the red line number. On my PSD it was 2800.

Personally, I don't like to see over 1325 for any length of time, but there are a lot of valid opinions out there. My EGT warning is set at 1280, so I can watch it.

I set my backdown at 1250 and my warning at 1280, that way I can let off the pedal if the edge is backing it down fast enough. I raise it slightly when pulling over the passes because it's very easy to hit those #'s when pulling.

D

I the equipment I run isn't of the same design as gm's trucks, but there is still a cool down time for our new equipment. On the other hand I have seen guys shut down equipment at WOT after running it hard for 8-10 hrs, and never seen a turbo go. Its your truck shut it down how ever you want. I would let it cool down; I wouldn't even shut down my gasser when it’s running hot.

My LLY bone stock before any mods (just gauges) would get 1350 pulling no trouble at all

Any time I have been doing anything but coasting down my 1/2 mile road to the stables, I allow anywhere from a 1 minute to 5 minutes of cool down. Pulling westbound out of Coachella, CA, there is a loooooong pull with a rest area at the top. I can pull off and still see 600+ when I stop, so I use 1800 rpm fast idle for a minute, then 1200 for a 2 or 3, and then let it idle to 325 before I shut down. In other words, cool down should depend on conditions as well as on temps. I do believe that turbos will last longer when treated this way.

In Australia where I grew up some of the diesel trucks come from factory with turbo timers