Failure mode - Cummins 6.7L ISB Diesel (Ram HD, 2019+ generation)

EGR cooler failure (2019+ 6.7)

Reliability tier: verified - verify before ordering, see /disclosure/

Symptoms

coolant drop with no external leak; white smoke on cold start
soot-clogged cooler banks after long idle-heavy service

Compare with the other causes of the same sign on this engine: white smoke from the exhaust (3 causes) · losing coolant (2 causes)

Root cause

The 2019+ 6.7 carries the 2013+ family EGR hardware; coolers clog/leak with mileage and duty cycle the same way, and a leaking cooler feeds coolant into the intake/exhaust path.

Diagnosis

pressure-test the cooling system; inspect for coolant in the EGR path and intake sooting
read EGR delta DTCs before replacing hardware

Fixes

replace the EGR cooler assembly with the gaskets/seals for the job ()

6.7L Cummins EGR Cooler, 2019+ (OEM Mopar)
egr-cooler-seal-kit - more than one option: 6.7L Cummins EGR Tube Gasket (Mopar 4627611AA, through 2020), 6.7L Cummins EGR Valve Gasket (Mopar 4627541AC)

Prevalence

common

Parts for this repair run about $90-$1,200: see them next to the other repairs on this engine in repair costs.