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Turbocharger vanes stick, or the turbo fails

The fourth-generation diesel uses a variable-vane turbocharger, and the vanes that make it flexible are also what soot sticks to. The cited source names the causes as oil-related — long oil change intervals, the wrong oil specification, and not letting the engine warm up or cool down — and separates two outcomes: a vane mechanism that has gummed up, which can sometimes be cleaned if it is caught early, and a turbocharger whose bearings have failed, which cannot. This is a single source, so the tier is the site's weakest, but the ordering it implies is sound and cheap to follow. Before either of those, eliminate a boost leak: a split intercooler hose or a loose clamp gives the same flat, smoky, comes-and-goes performance for the price of a clamp. If the turbo is passing oil, it is feeding the intake, and continuing to drive it hard risks the engine running on its own oil — which is why this is not filed as drive-normally.

Gen 42006–2021CR · UK · AU · JDM · EU · ME · GLOBALDamages other partsAnecdotal

Drive gently — repair soonManeje con cuidado — repare pronto

Anecdotal. This entry is not backed by factory documentation — treat its values and steps as a starting point, not as if they came from the factory manual.

Anecdótico. Esta entrada no se apoya en documentación de fábrica — tome los valores y los pasos como punto de partida, no como si vinieran del manual de fábrica.

Symptoms

  • Heavy black smoke under load
  • Blue or white smoke at idle or on start-up
  • A whine, siren or rattle from the turbocharger that rises with engine speed
  • The truck pulls strongly sometimes and flat at others, with no pattern you can pin down

Likely causes

  1. The variable vane mechanism is gummed up with soot and no longer moves freely
  2. The turbocharger bearings have failed and the shaft has play
  3. Long oil intervals, the wrong oil specification, or no warm-up and cool-down time
  4. A split hose or loose clamp in the intercooler pipework is losing boost

Diagnostic steps

  1. Ask for the oil service history and check both the interval and the oil specification used, because that is the cause the source names firstPoints toLong oil intervals, the wrong oil specification, or no warm-up and cool-down time
  2. Go over every intercooler hose, joint and clamp looking for splits, oil and slack before touching the turbochargerPoints toA split hose or loose clamp in the intercooler pipework is losing boost
  3. With the inlet pipe off and the engine stopped, check the compressor wheel for side play and for contact marks on the housingPoints toThe turbocharger bearings have failed and the shaft has playRules outThe variable vane mechanism is gummed up with soot and no longer moves freely
  4. Have the vane actuator watched or commanded through its travel with diagnostic equipment to see whether it moves smoothly and fullyPoints toThe variable vane mechanism is gummed up with soot and no longer moves freely

Fix paths

Clean and free the variable vane mechanism

$$Difficulty 4/5

Worth trying if the shaft is tight and the problem was caught early. It is not a fix for a turbocharger that is already passing oil or has bearing play.

Replace the turbocharger

$$$–$$$$Difficulty 5/5

Once the bearings have gone, replacement is the answer. Clean the intercooler and pipework of oil at the same time, or the debris left in there goes straight through the new unit.

Return to correct oil servicing

$–$$Difficulty 2/5

The right oil specification, the right interval, and the discipline of letting the engine idle a moment before shutdown after a hard run. This is what stops the replacement turbocharger going the same way.

Find and seal the boost leak

$Difficulty 2/5

The cheapest thing on this page and the first to eliminate. A leak makes a perfectly healthy turbocharger feel dead.

Sources

  1. Mitsubishi Pajero 4x4 Life — "Pajero 3.2 DI-D common problems": lists turbocharger failure on the third and fourth generations, notes the fourth generation uses a variable vane turbocharger, gives symptoms of excessive black smoke under load, blue or white smoke at idle and a whining or rattling noise, attributes the cause to "extended oil change intervals, incorrect oil specification, or insufficient warm-up and cool-down periods", and offers variable vane actuator cleaning as the fix if caught earlyOwner forumarchived copy