Exhaust Gas Temps- What should I be seeing?

[ToddMcMilian]

I read on here the other day where someone had mentioned they try to keep the exhaust gas temps at 600 degrees or below when towing and today I spent a little more time eyeballing my Edge CTS and I am all over the place temp wise....I was just driving to work and at one point I saw 646 degrees, it worked back down to upper 500's but never lower. Is that because I am getting temps via the CTS vs where a pyro would be reading? What should I be seeing temp wise for non-loaded conditions? I know there are probably 3000 variables to that but is there a general range ?

Thanks!!!!!!

 

[Bob4x4]

If your truck is stock there is nothing to be concerned with.Clessie Cummins determined many years ago that the best mileage was at around 600 and peak power at 1200-still pretty good rule today.With the aftertreatment equipped trucks the system is manipulated too much for any easy to use data by temp imho

 

[Jim W]

Todd, Please fill in your signature so we know what year of truck you have!

If you have 6.7L stock truck; in regen you could be as high as 1450F which you might get freaked out about. This is a normal temp during the regen process. When I was towing with a stock arrangement my EGT's would be around 800F and every two hundred to two hundred and fifty miles the truck EGT's would climb around 1200 to 1450F. This is when I know the truck was in regen and the fuel mileage would fall off in the overhead display.

 

[ToddMcMilian]

I appreciate the info, I haven't had this truck very long so I am trying to get ahead of maintenance items since they are unknowns and trying to get my learning on to make sure me and the truck have a long happy life together. Im now chasing an odd whine it has. I have an aftermarket warranty on it so I want to make sure I get anything fixed that is covered before it runs out. I love this site!

 

[DDT]

I am new to the 6.7 as well. My EGT run much hotter than 5.9 which I understand that. The cool down time to get to 350* takes a lot longer than 5.9 did. about 5 min when empty is this normal? It still has smog crap installed from OEM. I assume this is why. On the up side in colder temps the engine warms up much faster than 5.9.

 

[Jim W]

Hi; this issue was hotly debated when the first 6.7L Cummins went on sale in the 2007.5 and 2008 model years. The consensus was if the truck is stock, it is a waste of fuel to let the truck idle down to 350F. It also leads to more regens do to the DPF filling up with more soot, do to idling. The opinion was to allow the truck to idle a couple of min's to reach 400F to 450F than shut down. If you are towing a heavy load or for a long period of time we all agreed to allow the truck to idle for 5 to 10 min's before shutting down.

I have been towing an RV every since I bought my 08 new. My way of letting the truck to cool down after towing on the interstate. When pulling into the rest stop allow the truck to idle a few min's as you check the trailer tires with an IR heat gun. Going back to the truck shut the engine off this has always been enough time to allow the turbo to cool.

Hope This helps?

 

[tommyturbo]

JimW. You are right about the slow EGT cool down. Just parking in the driveway every night and shutting down would take about a minute
to reach 400F. After that, the temp took forever to reduce, so I kept with the 400F. Of course I use the EB full time and also for quicker warm ups.
It was just a few years ago that I began switching off the EB during shutdown. I noticed the EGT would reduce on down toward 350F in about the
same amount of time.
Tom

 

[cerberusiam]

Wet stacking start around 420 degrees EGT temp, no reason to cool it down any further than that. The 350 number is old school from 12V days that had a LOT different tune up and cool down timing. The only reason to cool it down is if you are at some high number like 800 or 900 and you pull immediately to a stop. Normal routines like pulling off for fuel or into a parking lot already cool the engine down enough. The waste of fuel and engine wear is not worth the attempt to follow outdated logic.

 

[DDT]

Thanks for the info guys. What is wet stacking?

 

[Sleeper1]

Wet stacking is a condition in diesel engines in which not all the fuel is burned and passes on into the exhaust side of the turbocharger and on into the exhaust system. The word "stacking" comes from the term "stack" for exhaust pipe or chimney stack. Google is a awesome tool!

 

[cerberusiam]

What goes out the exhaust system is not the problem, the fuel that is washing down the cylinder walls and into the oil is the issue. With the retarded timing of modern diesels it fuel contamination of the oil becomes much of an issue. Any time there is inadequate heat to at least partially burn the fuel it is an issue.

 

[photowrite]

Comparing my 2014 6.7 EGT at the EGT1 sensor via an Edge Insight, and the times 'recommended' based on the usage in the owner's manual, it appears that 400 degrees is plenty low. It genrally takes longer than the 'owner's manual times' to reach 400, sometimes much longer.

This same info and discussion was in another very recent thread, and also in my Still Plays With Trucks TDR magazine column.

Heck, in decades past I typically used 300 degrees not 350 (thermocouple pre-turbo in manifold), which didn't take too long to reach most of the time.

James

 

[mwilson]

Wet stacking is a condition in diesel engines in which not all the fuel is burned and passes on into the exhaust side of the turbocharger and on into the exhaust system. The word "stacking" comes from the term "stack" for exhaust pipe or chimney stack. Google is a awesome tool!

Google is great, but I have an actual speciman out in the yard. Our 6-71 powered yard horse wet stacks or as we call it ..."drools" out the stack..

 

[DDT]

Thanks to all, The knowledge of this board great. Im thinking 450* pre is cool enough.

 

[AH64ID]

Thanks to all, The knowledge of this board great. Im thinking 450* pre is cool enough.

That's pretty hot for pre...