1994 TOYOTA PREVIA

Typical onset: 100,000-150,000 mi

Symptoms: Blue smoke on startup or acceleration, Rapid oil consumption (quart every 500-800 miles), Metallic knocking from engine bay, Check engine light with knock sensor codes, Catastrophic failure: sudden loss of power and seized engine

Fix: The supercharger oil feed line cracks from heat cycling, starving the SC bearings which then fail and dump metal into the oil system. This destroys bearings throughout. If caught early (smoking stage), SC rebuild runs 8-12 hours. If you grenaded the bottom end, you're looking at engine-out rebuild or short block replacement at 25-35 hours labor due to mid-engine placement—must drop entire subframe.

Estimated cost: $800-1,500 for early SC repair; $4,500-7,000 for full engine rebuild with access time

Typical onset: 120,000-180,000 mi

Symptoms: White exhaust smoke, Coolant loss with no visible leaks, Overheating in traffic or hills, Milky oil on dipstick or oil cap, Bubbles in coolant reservoir when running

Fix: The mid-engine location traps heat and the 2.4L runs hot under the supercharger. Head gasket goes, usually between cylinders 2-3. Job requires engine removal or lifting cab (both awful). Most shops pull the engine. 18-24 hours labor, always resurface the head, replace timing belt/water pump while in there. High failure rate even after repair if cooling system isn't perfect.

Estimated cost: $2,800-4,200

Typical onset: 80,000-140,000 mi

Symptoms: ATF puddles under driver side front area, Pink fluid dripping from front subframe, Transmission slipping or delayed engagement when fluid gets low, Burning smell after highway driving

Fix: Steel cooler lines from transmission to radiator rust through where they route near the exhaust. Line replacement is 3-4 hours but requires subframe access. Some shops route aftermarket braided lines for $200 extra to avoid future failures. If you ran it low on fluid, expect internal transmission damage requiring rebuild (12-16 hours).

Estimated cost: $400-700 for lines only; $2,200-3,200 if transmission needs rebuild

Typical onset: 90,000-130,000 mi

Symptoms: Clunk when shifting from Park to Drive or Reverse, Vibration at idle that smooths out at speed, Driveline shudder on acceleration, Visible sagging of exhaust or transmission from underneath

Fix: The rear transmission mount (also supports the mid-mounted engine) disintegrates from heat and age. Allows excessive drivetrain movement. Replacement is 2-3 hours and requires supporting the entire powertrain. OEM mount is $180-250, aftermarket $80-120 but fails faster. Often done with oil cooler lines since access is similar.

Estimated cost: $300-500

Typical onset: 100,000-160,000 mi

Symptoms: Hard starting especially when hot, Stumble or hesitation under acceleration, Stalling in hot weather after short stops, Whining noise from rear cargo area

Fix: In-tank fuel pump runs hot and the filter (separate, under driver door area) rarely gets changed. Clogged filter kills the pump. Filter replacement is easy (1 hour), but pump requires dropping the fuel tank (4-5 hours). Many shops replace both together if pump is original. Preventive filter changes every 30k would avoid this.

Estimated cost: $120-180 for filter; $600-900 for pump and filter

Typical onset: 140,000-200,000 mi

Symptoms: Excessive blue smoke on deceleration, Oil consumption 1 quart per 500 miles or worse, Loss of power and boost, Rough idle with misfire codes, Pressurized crankcase (oil cap pops off)

Fix: High heat and supercharger boost stress cause ring land cracking on pistons 2 and 3. Requires full teardown with piston and ring replacement minimum (20-25 hours engine-out), often find scored cylinder walls requiring bore/hone. Short block replacement is often more cost-effective. No shade-tree fixes for this one.

Estimated cost: $3,500-5,500 for rings and pistons; $4,500-6,500 for short block