1991 NISSAN PICKUP

Typical onset: 120,000-180,000 mi

Symptoms: White smoke from exhaust on cold start, Coolant loss with no visible leaks, Oil that looks milky or foamy, Overheating under load, Bubbles in radiator when running

Fix: Head gasket replacement on KA24E is 8-10 hours labor, includes resurfacing head if warped. VG30E is worse at 12-15 hours because both heads need to come off and you're fighting tight engine bay access. Must pressure-test cooling system and check for head warpage—many shops see .008-.012" out of spec requiring machine work. If owner drove it hot repeatedly, expect cracked head or damaged pistons requiring full rebuild.

Estimated cost: $1,200-2,200 for gaskets alone, $3,500-5,500 if rebuild needed

Typical onset: 150,000-200,000 mi

Symptoms: Rattling noise on cold start for first 10-15 seconds, Rough idle, Check engine light with timing-related codes, Metal shavings in oil filter

Fix: The KA24E uses a timing chain with plastic guides that deteriorate. Front cover comes off, replace chain, guides, tensioner, and both sprockets. 6-8 hours labor. Not interference engine so no valve damage if it jumps, but you'll have a no-start. Do water pump while you're in there since you're 80% of the way there already.

Estimated cost: $800-1,400

Symptoms: Transmission fluid puddle under engine bay, Pink or red fluid on ground, Slipping gears after fluid loss, Burnt transmission smell

Fix: The steel cooler lines rust through where they connect to radiator, especially in salt states. Once they leak, you lose 6+ quarts fast and cook the transmission. Replacement is 2-3 hours including fabricating or sourcing new lines—OEM discontinued, so shops use universal with flare fittings. If caught early just lines and fluid. If driven low on fluid, expect internal clutch damage requiring transmission rebuild at 12-16 hours.

Estimated cost: $300-500 for lines, $1,800-2,800 for rebuild

Typical onset: 80,000-140,000 mi

Symptoms: Oil smell in cabin when heater is on, Oil coating on exhaust manifolds, Oil pooling on top of engine, Smoke from engine bay after highway driving

Fix: Both valve covers leak on V6 models due to age-hardened gaskets and warped covers. Oil drips onto exhaust creating smoke and smell. Replacement is straightforward but time-consuming due to accessory removal—4-5 hours for both sides. Clean mating surfaces thoroughly and check cover flatness. Use OEM gaskets, aftermarket ones leak within a year.

Estimated cost: $400-700

Typical onset: 100,000-160,000 mi

Symptoms: Fuel gauge reads empty when tank is full, Erratic gauge movement, Gauge stuck at one position, No gauge movement at all

Fix: The float arm corrodes or the rheostat wears out. Requires dropping fuel tank—2-3 hours labor. Nissan sending units are available but expensive; some shops retrofit universal units. Not a safety issue but annoying. Check wiring connector at tank first before replacing unit—corrosion there causes same symptoms.

Estimated cost: $350-550

Typical onset: 100,000-180,000 mi

Symptoms: High idle 1,200-1,500 RPM, Rough idle when cold, Hissing sound from intake, Poor fuel economy

Fix: The throttle body base gasket hardens and creates vacuum leak. 1-2 hours to remove throttle body, clean mating surfaces, replace gasket and idle air control valve gasket while you're there. Spray carb cleaner around base while running—RPM will spike if leaking. Simple fix that dramatically improves driveability.

Estimated cost: $150-300

Typical onset: 90,000-150,000 mi

Symptoms: Grinding or humming noise that increases with speed, Steering wheel vibration, Loose or wobbly feeling in steering, Noise changes when turning left or right

Fix: 4WD models use serviceable bearings that need periodic repacking, but most owners neglect this. 2WD uses sealed units. Either way, they fail from age and contamination. Replacement is 2-3 hours per side including hub removal and seal replacement. Must torque spindle nut precisely—too tight causes premature failure, too loose creates play. Road-test after to verify noise is gone.

Estimated cost: $300-500 per side