Is it necessary to idle the engine after a hard pull or highway speed to allow the turbo to cool before shut down? Maybe just the older models. One of my techs had a 6.4 and he followed this rule. One Friday after leaving work he stopped by the tavern and had a few beers. When he got home he let the truck idle while he rushed in to take a leak. The next morning after sleeping late he went out to find his truck still running. It should have been cooled down after 10 hours!

 

That prolly taught him a lesson...
If it's normally driving, I don't let it cool down. If it's really hot out, I've been towing or beating on the truck, I let it cool down for a few minutes, but that's about it.

 

I usually let her idle while I unhook.

 

Yup just depends on how I'm driving the truck. Normally I just give it a few and shut down when my egts become stable.

 

I idle it after long highway/towing runs. Bout it.

 

My goal is to see EGT1 under 400F. Normal driving, it isn't an issue. Towing the toy hauler in the Summer months, it can take several minutes. When I stop for fuel with the toy hauler, I always leave the truck run because I can usually fuel up and be back on the road before the EGT gets low enough to shut it off anyway.

The issue of turbo cool down hasn't really changed over the years. The concern is that when you shut the engine down, oil flow to the turbo stops as well. Now you potentially have turbo bearings at 500+ degrees and most conventional oils start to break down and leave deposits at temperatures far less than that. Turbos by nature are precision balanced with very tight tolerances. Imagine what those deposits can do to the bearings over time. This is more of a concern for turbos using a bushing type bearing than it is for ball bearing types, but they both can be affected.

 

Yes and if you catch it during a regen, EGT1 can be much higher. I always watch for that too. Just wondering if these exhaust filter systems are indirectly causing some of the turbo failures?

 

Matt, thanks for the explanation.

Our owners manual:
"To prolong engine life (especially after extended high speed, high ambient temperature or high GVW/GCW operation, such as heavy loads and/or heavy trailers, it is recommended that a hot engine be idled for 3-5 minutes which will allow the turbocharged engine to cool down"

 

I will idle while on the road towing and filling up at fuel stops. Unload then not too much.

About 3-5 minutes usually does it unless you have been pulling hard.

 

I always have a trailer and usually drive 500 miles 3 or 4 days/week. I start my engine in the morning, drive all day and shut it down when I get to a hotel. I let it idle for fuel and potty breaks and while I unload at the hotel.

Always do this, my idle time is around 20%, added plus is the radio! HVAC! nav! and cb are all still set and running. It's a pain to go through all that stuff sometimes.

I like the idea of cooling the motor down now and then but don't really know how important it really is.

 

Only real importance here is the turbo. Being cooled by oil. If it is really hot and you shut it down will still spinning 50K rpms then that is not good.

Based upon your comments and routine I would not change a thing. You are already accounting for the cool down.

 

Would using a synthetic oil also be helpful? Don't the synthetics have a better tolerance and not break down at higher temps? (Rotella T6).

 

imho, synthetic would just be a waste unless you are in a cold climate.

 

Synthetics definitely break down at higher temperatures so that would allow for higher shutdown temps. Just remember that the word "synthetic" is a relative term and not all "synthetic oils" are created equal. I would suggest viewing the data sheets on the specific oil you are using.

 

Yep it's nice and cold here! 0w-40 it is!