Toyota Supra (A80), Known Issues and Common Problems
Overview
The Toyota Supra A80 (1993-2002) has a reputation for bulletproof reliability, and there’s truth in that, the 2JZ engine is one of the most overbuilt production engines ever made. But the Supra is more than its engine. The sequential turbo system, the ageing electrical components, the increasingly scarce interior parts, and the consequences of decades of modifications by owners of varying skill levels all contribute to a list of issues that buyers need to understand.
The A80 is now 24-33 years old. Even the newest examples have spent over two decades accumulating wear, and many have been modified, sometimes multiple times. The problems below range from factory design characteristics to age-related failures to modification-induced issues.
Engine, 2JZ-GTE (Twin Turbo)
Sequential Twin-Turbo System Failures
What happens: A flat spot or hesitation in the 3,500-4,500 RPM range during full-throttle acceleration. Boost may spike or surge unpredictably. The car feels fast below 3,500 RPM and above 5,000 RPM but stumbles in the transition zone.
Why it happens: The sequential twin-turbo system uses a primary turbo at low RPM and transitions to both turbos above ~4,000 RPM. This transition is managed by a complex system of vacuum-actuated valves, solenoids, and an exhaust gas control valve (EGCV). After 25+ years, these components fail:
- EGCV (Exhaust Gas Control Valve): Sticks open or closed, preventing proper exhaust routing between the turbos.
- Vacuum solenoids: Six solenoids control the transition sequence. Any failure disrupts the transition.
- Vacuum lines: The rubber vacuum lines crack and develop leaks, causing erratic valve operation.
- Pre-turbo exhaust bypass valve: Sticks, preventing the secondary turbo from receiving exhaust gas.
How to fix it: Diagnosis requires methodical testing of each component in the sequential system. Replace all vacuum lines with silicone hose as a first step ($50, one afternoon). Test each solenoid individually. The EGCV can be cleaned or replaced ($200-400). For a comprehensive fix, rebuild the entire sequential system with new solenoids, actuators, and gaskets ($1,000-2,500).
Alternatively, delete the sequential system entirely and run a single larger turbo. This is a common modification that simplifies the system dramatically. A quality single-turbo conversion using a BorgWarner or Garrett turbo with a proper manifold and tune runs $3,000-8,000 depending on the turbo size and supporting modifications.
Severity: Needs attention. The car is still driveable but lacks full power in the transition zone. Left unaddressed, it can cause boost spikes that stress other components.
Turbo Seal Wear (High Mileage)
What happens: Blue smoke on cold startup (oil pooled in the turbo housing overnight drains into the exhaust when started). Blue smoke on deceleration (intake manifold vacuum pulls oil past the compressor seals). Oil residue in the intercooler piping. Increased oil consumption without external leaks.
Why it happens: The CT-20 turbochargers use oil-fed journal bearings with carbon face seals. After 150,000+ km, the seals wear and allow oil to migrate past the turbo shaft into either the exhaust (turbine side) or the intake (compressor side). Heat cycling accelerates seal degradation.
How to fix it: Rebuild both turbochargers. A turbo specialist can reball and reseal the CT-20s for $600-1,200 (both turbos). This is worthwhile if you’re keeping the sequential system. If you’re planning a single-turbo conversion, simply do the conversion and discard the worn CT-20s.
While the turbos are out, replace the oil feed and drain lines. Restricted oil drain lines (from carbon buildup) are a common secondary cause of turbo seal failure, the oil can’t drain fast enough and builds pressure behind the seals.
Severity: Needs attention. Oil consumption increases, and oil in the intake reduces charge air density. Not immediately dangerous but degrades performance.
Timing Belt Failure
What happens: Catastrophic engine damage. The 2JZ is an interference engine, if the timing belt breaks, the pistons strike the open valves, bending them and potentially damaging the pistons, head, and block. The engine stops instantly and will not restart.
Why it happens: The timing belt is a rubber component with a finite service life. Toyota specifies replacement every 100,000 km or 7 years. Many A80s have changed hands multiple times, and the timing belt service history may be incomplete or unknown.
How to fix it: Replace the timing belt, water pump, belt tensioner, and both idler pulleys as a set. Do not replace just the belt, the tensioner and idler bearings have the same service life and a failed tensioner will throw the belt. Use genuine Toyota or Gates Racing parts. Cost: $800-1,500 including parts and labour. This is a moderately involved job (6-8 hours) that requires removing the front of the engine.
If the belt has already broken: The head will need to come off for valve replacement and inspection. Budget $3,000-6,000 for a head rebuild after a timing belt failure, assuming the block and pistons are undamaged.
Severity: Critical. A timing belt failure destroys the engine. This is a non-negotiable maintenance item.
Cam Cover Gasket Oil Leaks
What happens: Oil seeps from the edges of the cam covers (rocker covers), running down the sides of the engine. Oil smell from the engine bay. Oil drips onto the exhaust manifold (fire risk on the turbo side).
Why it happens: The rubber cam cover gaskets harden and shrink over time, losing their seal. The half-moon seals at the rear of the cam covers are particularly prone to leaking.
How to fix it: Replace the cam cover gaskets and half-moon seals. This is a straightforward job, remove the cam covers, clean the sealing surfaces, and install new gaskets. Use genuine Toyota gaskets. Cost: $100-200 for parts, 2-3 hours of work. Apply a small bead of RTV sealant at the corners where the cam cover meets the head, these are the most common leak points.
Severity: Needs attention. Oil on the exhaust manifold is a fire hazard.
Oil Cooler O-Ring Leak
What happens: Oil leak from the oil cooler housing on the front of the engine, typically dripping down onto the oil filter and undercarriage.
Why it happens: The O-ring seal between the oil cooler and the engine block hardens with age and heat.
How to fix it: Replace the O-ring. The oil cooler assembly unbolts from the front of the block. Cost: $20 for the O-ring, 1-2 hours of work. While it’s apart, flush the oil cooler core, they can clog with sludge on neglected engines.
Severity: Needs attention. An oil leak is always a concern, and this one is easy to fix.
Engine, 2JZ-GE (Naturally Aspirated)
VVTi Solenoid Issues (Later Models)
What happens: Rough idle, loss of mid-range torque, check engine light. Fault codes related to Variable Valve Timing.
Why it happens: The later 2JZ-GE engines (1997+) feature Toyota’s VVTi system. The VVTi oil control valve (solenoid) can clog with oil sludge, preventing proper cam timing adjustment.
How to fix it: Remove and clean the VVTi solenoid with carburettor cleaner. If cleaning doesn’t resolve the issue, replace the solenoid ($100-200). Regular oil changes with quality oil prevent this issue.
Severity: Needs attention. The engine runs but with reduced performance and efficiency.
Transmission
V160 Getrag Synchro Wear
What happens: Crunching or grinding when shifting into 2nd or 3rd gear, particularly during quick downshifts when cold. The synchros may improve once the gearbox oil warms up.
Why it happens: The V160 synchros wear over time, particularly in cars that have been driven hard or used for drifting. The V160 is a strong gearbox but the synchros are not indestructible. Using incorrect gearbox oil (too thin) accelerates wear. The V160 specifies 75W-90 GL-4, do not use GL-5, as the EP additives can damage the brass synchros.
How to fix it: A synchro rebuild by a gearbox specialist runs $2,000-4,000. This is an expensive repair but far cheaper than replacing the entire gearbox ($5,000-10,000 secondhand). For a temporary measure, switching to Redline MT-90 or Motul Gear 300 (75W-90 GL-4) can improve shift quality by providing better synchro lubrication.
Severity: Needs attention. Worn synchros eventually prevent gear engagement entirely.
Auto-to-Manual Conversion Issues
What happens: Various driveability problems on cars that have been converted from automatic to manual transmission, clutch engagement problems, speedometer not reading correctly, ABS faults, reverse light not working, ECU issues.
Why it happens: The auto-to-manual conversion requires changes beyond just the gearbox. The pedal box, master cylinder, clutch hydraulic line, driveshaft, ECU (auto and manual ECUs have different programming), instrument cluster (speedometer signal differs), and reverse light switch all need to be addressed. Many conversions are incomplete, the converter does the mechanical work but skips the electrical integration.
How to fix it: Systematically address each system:
- ECU: Needs to be a manual-spec ECU, or the auto ECU needs the transmission programming modified.
- Speedometer: The auto uses a VSS from the transmission; the manual uses a different signal. The instrument cluster may need a speed signal converter.
- ABS: The ABS system reads wheel speed differently with the manual trans. If the ABS light is on after a conversion, the speed signals aren’t integrated correctly.
- Reverse lights: Wire the reverse light switch from the manual gearbox to the existing reverse light circuit.
A thorough conversion that addresses all these points costs $5,000-10,000 total. A dodgy conversion that only does the mechanical swap costs less but leaves you with a car that has multiple electrical issues.
Severity: Varies. Mechanical issues are urgent; electrical issues are annoying but not usually dangerous.
Cooling System
Radiator Degradation
What happens: Engine temperature creeps up in traffic or on hot days. Coolant loss. Green or pink coolant stains on the front of the engine or on the ground beneath the car.
Why it happens: The factory radiator is an aluminium-core, plastic-tank design. The plastic tanks become brittle with age and develop cracks at the crimped seams where they join the core. The core itself can clog internally from sediment in old coolant.
How to fix it: Replace with a full-aluminium aftermarket radiator ($300-600). This is one of the best value upgrades on any A80, the all-aluminium unit provides better cooling, eliminates the plastic tank failure point, and lasts indefinitely. While replacing the radiator, flush the entire cooling system, replace the thermostat ($30-50), and install new upper and lower hoses.
Severity: Urgent. Overheating can cause head gasket failure (even on a 2JZ, though it’s far less common than on the 7M) and warp the head.
Heater Core Leak
What happens: Sweet coolant smell inside the cabin. Fogging on the windscreen (coolant mist from the heater core mixing with cabin air). Coolant loss with no visible external leak. Wet carpets on the passenger side.
Why it happens: The heater core is a small radiator inside the dashboard that provides cabin heating. After decades, the thin tubes corrode and develop pinhole leaks. Contaminated or never-changed coolant accelerates corrosion.
How to fix it: Replace the heater core. On the A80, this requires significant dashboard disassembly, budget 6-10 hours of labour. The heater core itself is $100-200, but the labour makes this a $500-1,500 repair at a workshop. Some owners bypass the heater core (loop the hoses) as a temporary fix, but this means no cabin heating.
Severity: Needs attention. Coolant loss leads to overheating, and inhaling coolant vapour is unhealthy.
Body
Interior Trim Deterioration
What happens: The soft-touch coating on interior trim pieces becomes sticky, gummy, and eventually peels off in black flakes. Affects the centre console, door handle surrounds, and other trim pieces with the soft-touch finish.
Why it happens: Toyota used a rubberised soft-touch coating on interior plastics across many models in this era. The coating breaks down from UV exposure, heat, and the oils from hands. It’s a known Toyota deficiency that affects models from the 1990s and 2000s.
How to fix it: Strip the coating with isopropyl alcohol or a dedicated plastic coating remover. Sand the underlying plastic smooth, then either repaint with a textured trim paint or wrap in vinyl/leather. Alternatively, source replacement trim pieces from a wrecker, but they’ll likely have the same problem. Some owners send the trim pieces to a specialist for professional re-coating ($100-300 per piece).
Severity: Cosmetic only but extremely annoying. The sticky residue transfers to hands and clothing.
Dashboard Cracking
What happens: Cracks develop across the top surface of the dashboard, particularly near the windscreen and around the defroster vents. May start as a single crack and spread into a network of splits.
Why it happens: UV exposure and heat cause the dashboard material to become brittle over time. Australian sun is particularly harsh on these dashboards. Cars that have been garaged fare much better.
How to fix it: A replacement dashboard in good condition costs $1,000-2,000 from a wrecker (prices reflect the scarcity). Dashboard repair specialists can fill and re-skin cracked dashboards for $500-1,000. A dashboard cover or mat is the cheapest solution ($50-100) but changes the interior appearance.
Severity: Cosmetic, but affects the car’s value significantly at this price level.
Targa Roof Seal Deterioration
What happens: Water leaks into the cabin during rain or car washing. Stained headliner, musty smell, wet carpets.
Why it happens: Same as the A70, the rubber seals perish from age and UV exposure. The A80’s targa panel is aluminium and lighter than the A70’s, but the sealing principle is the same.
How to fix it: Replace the targa roof seals. Toyota still supplies these. Clean and lubricate the seal channels. Apply anti-seize to the targa bolts on reassembly. Cost: $200-400 for seals and installation.
Severity: Needs attention. Water ingress causes interior damage, corrosion, and electrical faults.
Electrical
Instrument Cluster Pixel Fade
What happens: The LCD displays in the instrument cluster (odometer, trip computer, clock) lose pixels, segments of the display stop working, making the readout unreadable.
Why it happens: The LCD displays use ribbon connectors that develop poor contact over time from thermal cycling. The solder joints on the circuit board can also crack.
How to fix it: The ribbon connector can be resoldered or replaced. Instrument cluster repair specialists can rebuild the display for $200-400. Some owners replace the entire cluster with a used unit from a wrecker ($300-600), but ensure the odometer reading is documented for compliance.
Severity: Minor but affects usability and roadworthiness (the odometer must be readable).
Wiring Harness Issues on Modified Cars
What happens: Random electrical faults, misfires, no-start conditions, erratic gauge behaviour, blown fuses, intermittent boost control problems.
Why it happens: Modified A80s often have wiring that’s been spliced, extended, and re-routed by multiple owners. Each modification adds potential failure points. Poor soldering, scotch locks, exposed splices, and incorrect wire gauges are all common.
How to fix it: For a car with extensive wiring issues, a complete engine harness replacement is often the most cost-effective solution. Aftermarket engine harnesses from Wiring Specialties and similar suppliers are available ($800-2,000). For targeted repairs, trace each fault systematically with a multimeter, repair with proper soldering and heat-shrink, and re-loom with split conduit.
Severity: Varies from minor annoyance to car-stopping. Electrical faults are the most common source of “it just won’t run right” problems on modified A80s.
Power Antenna Motor Failure
What happens: The power antenna doesn’t extend or retract, or extends/retracts partially. Grinding noise from the antenna motor.
Why it happens: The antenna mast cable (a toothed nylon strip) breaks or jams inside the motor housing. The motor itself can also fail electrically.
How to fix it: Replace the antenna mast and cable ($30-50 for the mast, 30 minutes to fit). If the motor has failed, replace the entire assembly ($100-200). Some owners delete the power antenna entirely and fit a stubby antenna or shark fin.
Severity: Minor. Cosmetic and functional annoyance only.
Fuel System
Fuel Pump Degradation
What happens: Engine stumble or cut-out under high boost/high RPM. Lean condition visible on wideband O2 gauge at full throttle. The engine may run fine at partial throttle but starve for fuel under maximum demand.
Why it happens: The stock fuel pump is adequate for factory power but marginal at higher boost levels. Even at stock power, a 25+ year old fuel pump has reduced output compared to new. Fuel delivery degrades gradually, so the problem develops slowly.
How to fix it: For stock cars, a new OEM-spec fuel pump restores original fuel delivery ($150-300). For modified cars, an upgraded fuel pump is essential. Common choices: Walbro 255lph ($100-150) for builds up to ~450 hp, Walbro 450lph or AEM 340lph for builds up to ~650 hp, and dual fuel pump setups for big-power builds. Any fuel pump change should be followed by a fuel pressure check at the rail under full load.
Severity: Urgent on modified cars. Running lean under boost causes detonation and engine damage.
Preventive Maintenance
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Timing belt every 100,000 km or 7 years. This is non-negotiable. Replace the water pump, tensioner, and idler pulleys at the same time. A broken timing belt destroys the engine.
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Replace all vacuum lines with silicone hose. The factory rubber lines crack and cause erratic boost control and sequential turbo transition problems. This is a cheap, easy job that prevents expensive diagnosis.
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Change engine oil every 5,000-7,500 km. Use 5W-30 or 10W-40 synthetic. The 2JZ’s oil galleries feed the turbos, clean oil is critical for turbo bearing life.
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Inspect the cooling system annually. Replace the thermostat every 5 years. Replace rubber coolant hoses every 10 years regardless of appearance. The plastic-tank radiator should be replaced with an all-aluminium unit proactively.
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Service the V160 gearbox oil every 40,000 km with 75W-90 GL-4. Not GL-5, the extreme-pressure additives in GL-5 attack brass synchros.
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Apply UV protectant to the dashboard and interior trim to slow the degradation of soft-touch coatings and dashboard material.
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Remove and re-grease the targa bolts twice a year if the car has a targa roof.
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Keep comprehensive records. At the price these cars command, documented service history directly affects value. Every service, every modification, every repair, keep receipts, photos, and dyno sheets.
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