N57 EGR cooler and turbo failure
Discussion
Looking for technical views from anyone familiar with the BMW N57.
Around 10-year-old 330d. It has had three EGR cooler replacements under BMW campaigns.
After the second EGR replacement the car subsequently developed intermittent engine-bay smoke, coolant loss and increasing oil top-ups. It later suffered a major smoke event and the turbo failed; the inlet manifold was also found cracked and was replaced at the same time.
Further BMW diagnostics subsequently identified severe EGR sooting, suspected EGR-cooler leakage and reduced flow through the cooler, as well as DPF/Lambda-related faults. The dealer considered the DPF/Lambda issues to be responsible for the warning light/running problems and said replacing the EGR would not improve them. The EGR cooler was nevertheless replaced for a third time, with no other repair carried out at the same time. The engine-management light then stayed off for about 2½ months, although the oil consumption/top-up issue continued.
More recently an oil leak from the rocker-cover area was repaired, and since that work the recurring engine-bay smoke, which had sometimes also entered the cabin, has largely if not totally disappeared. This makes me wonder whether the rocker-cover leak may have been responsible for the recurring engine-bay smoke throughout much of this period.
What I'm particularly trying to understand is the earlier turbo failure. Is there a technically credible mechanism on an N57 whereby an EGR cooler/EGR-system fault or previous EGR work, coolant leakage/ingress or resulting intake/boost disturbance could contribute to turbocharger failure?
Also, does anyone know of a BMW PuMA measure, ISTA test plan, SIB or other BMW technical document dealing with this particular relationship?
Interested particularly in technical evidence or experience of N57 failures rather than assuming that the faults must be connected.
Around 10-year-old 330d. It has had three EGR cooler replacements under BMW campaigns.
After the second EGR replacement the car subsequently developed intermittent engine-bay smoke, coolant loss and increasing oil top-ups. It later suffered a major smoke event and the turbo failed; the inlet manifold was also found cracked and was replaced at the same time.
Further BMW diagnostics subsequently identified severe EGR sooting, suspected EGR-cooler leakage and reduced flow through the cooler, as well as DPF/Lambda-related faults. The dealer considered the DPF/Lambda issues to be responsible for the warning light/running problems and said replacing the EGR would not improve them. The EGR cooler was nevertheless replaced for a third time, with no other repair carried out at the same time. The engine-management light then stayed off for about 2½ months, although the oil consumption/top-up issue continued.
More recently an oil leak from the rocker-cover area was repaired, and since that work the recurring engine-bay smoke, which had sometimes also entered the cabin, has largely if not totally disappeared. This makes me wonder whether the rocker-cover leak may have been responsible for the recurring engine-bay smoke throughout much of this period.
What I'm particularly trying to understand is the earlier turbo failure. Is there a technically credible mechanism on an N57 whereby an EGR cooler/EGR-system fault or previous EGR work, coolant leakage/ingress or resulting intake/boost disturbance could contribute to turbocharger failure?
Also, does anyone know of a BMW PuMA measure, ISTA test plan, SIB or other BMW technical document dealing with this particular relationship?
Interested particularly in technical evidence or experience of N57 failures rather than assuming that the faults must be connected.
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