1984 NISSAN PICKUP

Typical onset: 120,000-180,000 mi

Symptoms: Rattling noise on cold start that quiets after warmup, Metallic clatter from front of engine, Check timing marks - chain can jump teeth, Poor starting or backfiring through carb

Fix: Replace timing chain, guides, tensioner, and both sprockets while you're in there. Front cover comes off. Budget 6-8 hours for a thorough job including new front seal and water pump since it's exposed. The plastic guide rails crack and disintegrate - non-negotiable replacement.

Estimated cost: $600-1,200

Typical onset: 150,000+ mi

Symptoms: Progressive loss of power and compression, Excessive oil consumption, Hard starting when hot, Misfiring under load, Compression test shows uneven or low readings

Fix: These engines were designed for leaded fuel. Unleaded causes exhaust valve seats to recess into the head over time. Requires head removal, machining for hardened seats, valve job, and resurface. 12-16 hours labor. If caught early, sometimes a valve job alone buys time, but proper fix is hardened seats.

Estimated cost: $1,200-2,200

Symptoms: High idle that won't come down, Stalling when warm, Poor fuel economy (under 18 mpg), Rough idle, Hesitation on acceleration

Fix: The Hitachi carburetors develop vacuum leaks at the base gasket and throttle shaft bushings wear out. Vacuum lines become brittle and crack. Start with fresh vacuum diagram and methodical leak check. Carb rebuild kits run $40-80, but shaft bushings require machine work. Some opt for Weber 32/36 conversion ($300-400 in parts) which solves it permanently. 3-5 hours for proper carb service.

Estimated cost: $200-600

Typical onset: 80,000+ mi

Symptoms: Oil seepage down front or side of engine, Burning oil smell after driving, Oil spots on driveway, Low oil level between changes

Fix: The valve cover gasket cork dries out and the front crank seal behind the timing cover weeps. Valve cover is easy - 1 hour with gasket and RTV. Front seal requires timing cover removal, so do it when replacing timing chain. Combined 2 hours if doing valve cover alone.

Estimated cost: $150-300

Typical onset: 100,000-150,000 mi

Symptoms: Clutch pedal goes to floor and stays, Difficulty shifting or can't get into gear, Soft or spongy clutch feel, Fluid leak visible at master or slave cylinder

Fix: Both master and slave cylinders fail, often within a year of each other. Replace both simultaneously - penny wise, pound foolish to do one. Slave cylinder requires transmission removal on 4WD models (add 2-3 hours). 2WD is external and easier. Budget 3-4 hours for 2WD, 5-7 hours for 4WD including both cylinders and bleeding.

Estimated cost: $400-800

Symptoms: Visible rust perforation on frame rails, Leaf spring mounts rusted through, Body mounts deteriorated, Frame flex or cracking around rear spring hangers

Fix: Not a repair issue but a structural concern. In salt states, the frame rusts from inside out, especially behind cab and at rear spring hangers. Inspect carefully before purchase - if rear crossmember or spring mounts are compromised, truck is often not worth repairing. Some frames can be plated and reinforced (10-20 hours fabrication work), but most are totaled by rust.

Estimated cost: $2,000-5,000