Supra (A70)

1986-1993 / Coupe / Japan

All Supra (A70) problems All workshop issues

Common Engine, 7M-GTE (Turbo)

CT-26 Turbo Failure

Symptoms

Loss of boost pressure, excessive oil smoke (blue/grey) on startup or deceleration, whistling or grinding noises from the turbo, and oil in the intercooler piping.

Cause

The CT-26 has a limited service life. Shaft bearings wear, allowing the compressor and turbine wheels to contact their housings. Seal wear allows oil past the turbo seals into the intake (compressor side) or exhaust (turbine side). Running the turbo hard and shutting down immediately (no cool-down idle) accelerates seal and bearing failure.

Fix

Rebuild or replace.

A CT-26 rebuild runs $400-800 at a turbo specialist.

For anyone planning to increase power beyond stock, this is the time to upgrade.

Common replacements: Garrett GTX3076R for mild builds (300-450 hp), BorgWarner S362 for mid-range (400-550 hp), Garrett GTX3582R for serious builds (500-700 hp).

Upgrading from the CT-26 requires a new exhaust manifold (or adapter), oil and water lines, and an ECU retune.

Budget $2,000-5,000 depending on the turbo choice.

Cost mentioned in fix

$400-800Budget $2,000-5,000

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// More Supra (A70) problems

Other known issues

Common Engine, 7M-GTE (Turbo)

Head Gasket Failure

The head gasket blows, allowing coolant into the combustion chambers and/or oil passages. White smoke from the exhaust, coolant loss without visible external leak, overheating under boost, milky oil on the filler cap, and bubbles in the coolant overflow tank. In severe cases, hydrolock (coolant filling a cylinder and bending a connecting rod on startup).

Critical Engine, 7M-GTE (Turbo)

Low Oil Pressure at Idle

Oil pressure drops below 10 psi at hot idle. The factory oil pressure warning light may flicker or illuminate at idle, particularly in traffic on hot days. The engine may develop bearing noise (deep knocking from the bottom end).

Critical Engine, 7M-GTE (Turbo)

Cooling System Inadequacy Under Boost

Coolant temperature climbs rapidly under sustained boost, particularly in traffic or on hot days. The temperature gauge sits higher than normal and doesn't recover quickly.

Common Engine, 7M-GTE (Turbo)

Fan Clutch Wear

The engine runs hotter than normal, particularly at low speeds and idle. The cooling fan doesn't seem to pull much air through the radiator.

Critical Engine, 7M-GE (Naturally Aspirated)

Head Gasket Failure (Less Common)

Common Transmission

W58 Synchro Wear

Crunching or grinding when shifting into 2nd or 3rd gear, particularly when cold or during quick shifts. The synchros may improve slightly once the gearbox oil is warm.

View all 17 Supra (A70) problems