1998 TOYOTA T100

Typical onset: 150,000-200,000 mi

Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Milky oil on dipstick or oil cap, Overheating under load

Fix: Both head gaskets need replacement, heads should be checked for warpage and pressure tested. Budget 12-16 hours labor for both sides, includes timing belt replacement while you're in there. Many shops won't do one side only because the other follows within 20k miles.

Estimated cost: $2,200-3,500

Typical onset: 120,000-180,000 mi

Symptoms: Transmission fluid puddle under truck, often pink or red, Transmission slipping or delayed engagement after fluid loss, Visible corrosion or wetness at radiator cooler fittings

Fix: Steel lines rust through where they connect to the radiator's internal cooler. Replace both cooler lines, flush transmission, refill with Toyota Type T-IV. If caught early before running low on fluid, trans survives. If run low, expect internal damage requiring rebuild. Line replacement alone is 2-3 hours.

Estimated cost: $350-600 for lines only, $1,800-3,200 if transmission rebuild needed

Typical onset: 100,000-150,000 mi

Symptoms: Clunking over bumps from front end, Steering wander or looseness, Uneven tire wear on inside edges, Play visible when prying on tire at 6 and 12 o'clock

Fix: Lower ball joints are not serviceable separately on the 98 T100—you replace the entire lower control arm assembly. Both sides typically need doing within 10k miles of each other. 3-4 hours labor for both sides, includes alignment.

Estimated cost: $650-950

Symptoms: Surface rust penetrating through on frame crossmembers, Flaking or scaling on frame behind cab, Visible holes or structural weakness in frame, Most common in salt-belt states

Fix: The T100 wasn't included in Toyota's major frame recall like Tacomas, but similar rust patterns appear. Crossmember replacement or frame plating requires frame-off work or extensive subframe drops. 20-40+ hours depending on severity. Many trucks get totaled rather than repaired.

Estimated cost: $3,500-8,000+ or economic total loss

Typical onset: 150,000-220,000 mi

Symptoms: Click but no crank, Intermittent no-start, works after sitting, Grinding noise during start attempts, More common in hot weather after heat soak

Fix: Denso starters are usually reliable but the solenoid contacts wear out. Replacement starter is straightforward on the 2.7L I4 (1.5 hours), more involved on the 3.4L V6 due to access (2.5-3 hours). Rebuilt starters are hit-or-miss; OE Toyota or quality remanufactured recommended.

Estimated cost: $400-650

Typical onset: 180,000-250,000 mi

Symptoms: No start with crank but no fuel pressure, Stumbling or dying under acceleration, Intermittent stalling when fuel tank below 1/4, Whining noise from tank area before failure

Fix: In-tank pump accessed through bed removal or cutting an access panel in bed floor. Most techs drop the tank instead (safer for rust-belt trucks). 2.5-3.5 hours labor. Always replace fuel filter at same time—it's inline under the truck and rarely done.

Estimated cost: $550-850