Toyota Supra: Turbo oil drain restriction causing bearing wear and decel smoke

The twin turbos on the 2JZ-GTE rely on gravity-drain oil return lines that pass through a restricted banjo fitting. These lines accumulate carbon and sludge over high-mileage use, especially if oil changes were extended. Partial or full blockage causes oil to back up into the turbo centre housing, degrading bearings and forcing oil past the seals into the compressor side. The result is blue-grey smoke on deceleration and eventual bearing failure if ignored.

• Blue or grey smoke from exhaust on deceleration or lift-off
• Oil smell from exhaust
• Oil residue inside the intercooler piping or compressor inlet
• Turbo whine or roughness at high rpm

1. 1

   Remove compressor inlet hose and inspect inside of compressor housing for oil film.

2. 2

   Check oil return lines for restriction by attempting to blow through them when disconnected.

3. 3

   Inspect oil filler cap and dipstick area for heavy sludge indicating poor maintenance history.

Parts involved: Turbocharger.

$400 to $2,500 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “What is the oil change interval history?”
• “Has there ever been smoke from the exhaust?”
• “Have the turbo drain lines been inspected or replaced?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.