1991 TOYOTA SUPRA

Typical onset: 80,000-150,000 mi

Symptoms: White smoke from exhaust, Coolant loss with no visible leak, Overheating under boost, Milky oil on dipstick or cap, Rough idle when warm

Fix: The 7M-GTE's factory torque spec was inadequate—head gasket failure is nearly inevitable. Proper fix requires head removal, resurfacing (usually warped 0.003-0.008 in), ARP head studs instead of bolts, and metal head gasket. Budget 18-24 hours labor. While apart, replace timing belt, water pump, cam and crank seals. Many owners discover cracked heads during this job, adding $800-1,200 for replacement or repair.

Estimated cost: $2,800-4,500

Typical onset: 120,000-180,000 mi

Symptoms: Slipping between 2nd and 3rd gear, Delayed engagement into Drive, Shuddering on light throttle, Red fluid with burnt smell, Won't hold overdrive

Fix: The A340E behind the turbo motor wasn't built for sustained boost—clutch packs wear, valve body gets sloppy. Transmission oil cooler lines rust through and contaminate fluid, accelerating failure. Rebuild takes 12-16 hours, but many techs recommend replacement with low-mileage JDM unit (8-10 hours swap). Always replace cooler lines and flush external cooler during any trans work.

Estimated cost: $2,200-3,800

Typical onset: 100,000-200,000 mi

Symptoms: Deep knocking sound on cold start that fades, Metallic rattle under load, Low oil pressure at idle when hot, Metal shavings in oil filter, Sudden catastrophic knock and loss of power

Fix: Often caused by extended oil change intervals, cheap filters, or aggressive driving on worn bearings. If caught early with light scoring, you can get away with bearing replacement and crank polish (16-20 hours). If crank is grooved beyond 0.010 undersized, it needs grinding or replacement—at that point most owners opt for short block replacement or full rebuild with forged internals. Oil pump should always be replaced during bottom-end work.

Estimated cost: $3,500-7,500

Typical onset: 90,000-140,000 mi

Symptoms: Sluggish boost response, Boost creep (climbing past 8-9 psi), Exhaust leak ticking from engine bay, Check engine light for lean condition, Hissing sound under hood at idle

Fix: CT26 turbo wastegate actuators fail from heat cycling—diaphragm tears or rod seizes. Meanwhile, the cast exhaust manifold cracks between runners. Wastegate actuator alone is 3-4 hours (manifold removal required). If manifold is cracked, you're looking at 6-8 hours total with new turbo gaskets, manifold studs (they always break), and often new turbo oil feed line. Aftermarket tubular manifolds are common upgrades.

Estimated cost: $800-2,200

Typical onset: all mileages (age-related)

Symptoms: Hard starting when hot, Stumble or hesitation under boost, Fuel smell in cabin or trunk, Visible fuel weeping at filter or rail, Long crank before fire

Fix: Rubber fuel lines throughout the engine bay are 30+ years old and deteriorate from heat and ethanol. Fuel filter (in engine bay, not under car) clogs with rust from aging tank. Fuel pump wiring harness develops cracks. Proper fix involves replacing all rubber fuel lines, filter, pump sock, and cleaning or replacing tank sender. Labor is scattered—2 hours for lines/filter, 4-6 hours if tank needs dropping. This is maintenance, not optional.

Estimated cost: $600-1,400

Typical onset: 80,000-120,000 mi

Symptoms: Clunk when shifting into Drive or Reverse, Vibration at idle in gear, Excessive driveline movement over bumps, Visible transmission sag when inspected on lift

Fix: Rubber mounts fatigue and the transmission tilts rearward, stressing the shifter linkage and driveshaft. The large center crossmember mount is the main culprit. Replacement is straightforward—1.5-2 hours to support trans, remove crossmember, swap mount. Do engine mounts at same time if they're original (add 2 hours).

Estimated cost: $250-600