question about the 6.7 cummins

[avp12304]

im seriously considering buying a 2012 cummins so i dont have to mess with all that DPF mess, my question is, the 6.7 engine itself, what has changed from 2012 to the current 2021 6.7 other than the DPF stuff? are the 2012 6.7's just as good as today's as far as power and economy? have they changed anything?

 

[MoparProud]

First, 2012 has a DPF. All diesels from mid-2007 and up have a DPF.

What you’re wanting to avoid is DEF, which came out in 2013. This is silly and total garbage; the DEF system is WAAAAAAYYYYYYY more reliable and has a much longer service life than non-DEF, with greater fuel economy to boot.

If you’re keeping stock, DO NOT buy an ‘07-‘12 truck, as the emissions is total garbage. ‘13+ with DEF is the way to go. Not conjecture nor opinion. It’s stone cold fact beyond any contestation.

Oh, DPF is still on DEF-equipped trucks. DEF is fluid injected post-DPF to provide additional cleaning.

Minimal changes to the engine itself overall except for the ‘19 and newer trucks. New block, redesigned valve train, ‘19 and ‘20 have the garbage CP4 injection pump, etc

 

[crash68]

, DPF is still on DEF-equipped trucks. DEF is fluid injected post-DPF to provide additional cleaning.

DEF is injected post-DPF in all diesel after treatment exhaust systems. The fluid is injected into the Selective Catalytic Reduction (SCR) to reduce NOx.

 

[chri5k]

First, 2012 has a DPF. All diesels from mid-2007 and up have a DPF.

What you’re wanting to avoid is DEF, which came out in 2013. This is silly and total garbage; the DEF system is WAAAAAAYYYYYYY more reliable and has a much longer service life than non-DEF, with greater fuel economy to boot.

If you’re keeping stock, DO NOT buy an ‘07-‘12 truck, as the emissions is total garbage. ‘13+ with DEF is the way to go. Not conjecture nor opinion. It’s stone cold fact beyond any contestation.

Oh, DPF is still on DEF-equipped trucks. DEF is fluid injected post-DPF to provide additional cleaning.

Minimal changes to the engine itself overall except for the ‘19 and newer trucks. New block, redesigned valve train, ‘19 and ‘20 have the garbage CP4 injection pump, etc

Not quite. Myself and a number of others have had issues with the DEF system. Defective pumps, quality sensors, etc. that make the truck undriveable when they fail. Pumps have been on national back order for over a year. Also the DEF/SCR system is before the DPF in the exhaust system but it is not some exhaust system janitor. The catalyst in the SCR breaks down the NOx into nitrogen and oxygen. The DEF is a catalytic reaction action enhancer which is used up during the process.

 

[Travelin Ram]

First, 2012 has a DPF. All diesels from mid-2007 and up have a DPF.

What you’re wanting to avoid is DEF, which came out in 2013. This is silly and total garbage; the DEF system is WAAAAAAYYYYYYY more reliable and has a much longer service life than non-DEF, with greater fuel economy to boot.

If you’re keeping stock, DO NOT buy an ‘07-‘12 truck, as the emissions is total garbage. ‘13+ with DEF is the way to go. Not conjecture nor opinion. It’s stone cold fact beyond any contestation.

Oh, DPF is still on DEF-equipped trucks. DEF is fluid injected post-DPF to provide additional cleaning.

Minimal changes to the engine itself overall except for the ‘19 and newer trucks. New block, redesigned valve train, ‘19 and ‘20 have the garbage CP4 injection pump, etc

This is good advice, I had a 2011 and now a 2018. Don’t fall into the trap of listening to all the negativity on the internet. The majority of posts on ANY forum are about problems.

 

[MoparProud]

Not quite. Myself and a number of others have had issues with the DEF system. Defective pumps, quality sensors, etc. that make the truck undriveable when they fail. Pumps have been on national back order for over a year. Also the DEF/SCR system is before the DPF in the exhaust system but it is not some exhaust system janitor. The catalyst in the SCR breaks down the NOx into nitrogen and oxygen. The DEF is a catalytic reaction action enhancer which is used up during the process.

Yes I misspoke, DEF is sprayed before DPF.

I’m aware of what it does, however the DEF-equipped system is far superior than non-DEF used from ‘07.5-‘12. By every metric, the DEF system is better; it’s more reliable, it’s got better fuel economy, far more power, etc. Yes, everything can fail and will eventually, that doesn’t mean it’s not better.

It’s what we have to work with unfortunately

DEF is injected post-DPF in all diesel after treatment exhaust systems. The fluid is injected into the Selective Catalytic Reduction (SCR) to reduce NOx.

DEF is not on every after-treatment system. Cummins didn’t have it from ‘07.5-‘12

 

[crash68]

Not quite. Myself and a number of others have had issues with the DEF system. Defective pumps, quality sensors, etc. that make the truck undriveable when they fail. Pumps have been on national back order for over a year. Also the DEF/SCR system is before the DPF in the exhaust system but it is not some exhaust system janitor. The catalyst in the SCR breaks down the NOx into nitrogen and oxygen. The DEF is a catalytic reaction action enhancer which is used up during the process.

Yes I misspoke, DEF is sprayed before DPF.

I’m aware of what it does, however the DEF-equipped system is far superior than non-DEF used from ‘07.5-‘12. By every metric, the DEF system is better; it’s more reliable, it’s got better fuel economy, far more power, etc. Yes, everything can fail and will eventually, that doesn’t mean it’s not better.


DEF is not on every after-treatment system. Cummins didn’t have it from ‘07.5-‘12

I should have qualified my initial statement of diesel exhaust systems
that use DEF, but didn't think I would need to if a truck doesn't use DEF it doesn't have to spray the stuff.

Your both wrong, the SCR is after the DPF, so that makes it downstream and that's where the DEF is injected.

The DOC is located before the DPF and does not require DEF. In the Cummins exhaust there is a separate DOC located in the downpipe, other diesel exhaust systems have the DOC and DPF in one.
The DPF is #9 the SCR is #10

 

[chri5k]

I stand corrected. Thanks for the diagram Crash.

 

[John Jensen]

Here's another pic of the emissions system

 

[MoparProud]

I should have qualified my initial statement of diesel exhaust systems
that use DEF, but didn't think I would need to if a truck doesn't use DEF it doesn't have to spray the stuff.

Which makes a guy wonder what in the world you were initially trying to say when you quoted my original post. I’m still scratching my head on that one....

I did twist myself this morning. Of course DEF is post-DPF. Like I originally stated correctly. Has to filter before you can convert...

 

[Tach_tech]

For the most part the DPF systems are pretty reliable. I really don’t deal with to many DPF issues.

The DEF on the other hand seems to have its fair share of problems, especially once it gets to winter time.