2021 3.0l duramax silverado def questions

Joenelson123 · June 19, 2023

Hello,

I own a silverado with the 3.0 duramax and am just wondering about the regeneration

1. How often does it do a regen?

2. How long does it take?

3. How do I know it’s doing a regen? Smell?

Thanks

redwngr · June 20, 2023

Takes about 11 -13 miles, or about 10 minutes...

It does not tell you when it does a regen. If it happens on the highway you may not notice, unless you are watching a fuel economy screen (like the last 25 mile page)

If you happen to come to a stop during regen it may be idling a little faster.

Smell generally only occurs during first few regens. Presumably a '21 is beyond that stage.

There have been some trucks that had exhaust leaks. If you're smelling diesel exhaust take it in.

Miles between regens depends on how hard it is working. Harder work generally results in higher exhaust temps and also more miles between regens. Could be less than 200 miles or more than 600.

If a regen is interrupted (like arriving at destination) it will generally 'resume' next trip. If it was near completion, it may decide that it was 'close enough' for this regen.

None of your questions were about DEF (diesel exhaust fluid) questions -- the were DPF (diesel particulate questions)

Common misunderstanding that DEF is used for regeneration -- but it is not.

Regeneration uses extra fuel, injected directly into the exhaust system to heat the DPF to incinerate the collected soot.

DEF is used whenever the engine is running. It is injected with a DEF injector. DEF is used in a chemical process to reduce the NOx in the exhaust stream. (NOx is not the black soot that is associated with diesels)

DEF usage will be about 2% of fuel -- so for every 100 gallons of fuel it will use about 2 gallons of DEF.

The DEF gauge is very misleading -- don't use it as a method to estimate your miles per gallon of DEF.

The DEF system will give level warnings as it gets low. If it ever gets to empty, it will allow the truck to go another 500 miles before it starts the first speed limit.

Probably going to need fuel by then anyway, and almost any place that has diesel also has DEF. (most all on and off-road diesel today us def). Most all auto parts departments or auto parts stores also carry DEF.

Edited June 20, 2023 by redwngr