← Coolant loss on all engines

Symptoms · 6.7 Cummins 2019+

6.7 Cummins 2019+: losing coolant

2 documented failures on this engine list this among their signs. They are ordered from the most widespread down. Each one shows the signs in its record's own words, how to tell it from the others, the usual fix and any recall or bulletin.

1. EGR cooler failure (2019+ 6.7) Common
2. Head gasket failure on tuned 2019+ 6.7 Common

Not sure which engine you have, or want the recalls for your exact truck? Check your VIN: it names the engine and lists the campaigns for that model year. Whether a recall is still open on your VIN: nhtsa.gov/recalls.

1 EGR cooler failure (2019+ 6.7)

verified How widespread: Common

How it shows up

• coolant drop with no external leak; white smoke on cold start

Its other signs

• soot-clogged cooler banks after long idle-heavy service

How to tell it apart

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

Usual fix

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

Root cause, parts and sources →

2 Head gasket failure on tuned 2019+ 6.7

verified How widespread: Common

How it shows up

• coolant push-out under boost, combustion bubbles in the degas bottle

Its other signs

• returns on stock tune - the boost, not the cooling system

How to tell it apart

• combustion-leak test at the degas neck; log boost spikes
• check bolt-torque history before assuming the gasket alone

Usual fix

head gasket set with head studs (community-standard upgrade), deck check at machining

Root cause, parts and sources →

Other symptoms on the 6.7 Cummins 2019+

Hard start, long crank or no-startLoss of power, limp mode or derateWhite smoke from the exhaustTicking, knocking, rattle or whineDEF, DPF and regeneration warnings

Everything on the 6.7 Cummins 2019+Its recalls and bulletins

Order: how widespread each failure is in its record (near-universal, very common, common, occasional, rare), then the number of NHTSA owner complaints that match its keywords. Complaint counts are keyword matches, not a manual review of each complaint. A symptom listed here means the failure is documented with that sign; it is not a diagnosis of your truck. Tiers: verified, aggregated, contested, data-gap. How we tier and source facts.