Failure mode - Ford 6.7L Power Stroke Diesel (Scorpion)

EGR cooler thermal-fatigue coolant leak

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

Symptoms

white, sweet-smelling exhaust smoke, especially at idle after warm-up
unexplained coolant loss with no visible external leak
coolant odor from the exhaust or residue at the cooler-to-manifold joints
check-engine codes P045C and related cooler-performance codes

Compare with the other causes of the same sign on this engine: losing coolant (2 causes)

Root cause

The liquid-cooled EGR circuit routes hot exhaust gas through a coolant-fed heat exchanger (the cooler) before the EGR valve meters it into the intake. Repeated heating/cooling cycles fatigue the cooler's internal welds until coolant seeps into the exhaust stream and flashes to steam. Trucks that tow heavy in hot climates are the most prone to this thermal-fatigue leak (contrast EGR valve soot clogging / sticking's clogging mechanism, which is duty-cycle-opposite: short-trip/heavy-idle trucks).

Diagnosis

pressure-test the cooling system cold and watch for an unexplained pressure drop with no external leak
pull the EGR valve and inspect for wet, steam-cleaned intake passages, which indicate coolant intrusion rather than soot clogging
on higher-mileage trucks, plan to service the cooler and valve together - a clogged cooler that restricts flow will quickly foul a new valve

Fixes

replace the EGR cooler (a cooler with confirmed internal leakage cannot be cleaned back into service) ()

egr-cooler - more than one option: 6.7L Power Stroke EGR Cooler Upgrade with H-Core Technology, 2011-2024 (Bullet Proof Diesel), 6.7L Power Stroke EGR Cooler (Heat Exchanger), gen1/gen2, 6.7L Power Stroke EGR Cooler (Heat Exchanger), gen3

service the EGR valve and related coolant hoses in the same job ()

Prevalence

common

Parts for this repair run about $270-$910: see them next to the other repairs on this engine in repair costs.