Failure mode - Ford 6.0L Power Stroke Diesel

EGR cooler failure

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

Symptoms

white, sweet-smelling smoke from the exhaust on acceleration or at idle
coolant loss with no visible external leak
bubbles or pressure build-up in the degas bottle
overheating; low-coolant warning
rough running or misfire if coolant enters a cylinder

Compare with the other causes of the same sign on this engine: white smoke from the exhaust (3 causes) · losing coolant (5 causes) · overheating or temperature creeping up (6 causes) · misfire, rough idle, hesitation or surging (8 causes)

Root cause

The factory EGR cooler (square-tube design) fatigues and cracks under thermal cycling. Failure is accelerated by restricted coolant flow from a clogging oil cooler and by degraded / contaminated coolant. It routes hot exhaust gas through coolant; when it cracks, coolant enters the intake and combustion, or exhaust gas pressurises the cooling system.

Diagnosis

chemical combustion-gas test on the coolant (block test)
pressurise the cooling system and look for coolant entering the intake or exhaust
borescope the intake / EGR passages
watch degas bottle for exhaust-gas pressurisation with the engine running

Fixes

install an upgraded EGR cooler; ALWAYS replace or verify the oil cooler at the same time or it will fail again ()

coolant filtration and fresh spec coolant to prevent recurrence ()

Prevalence

near-universal