1995 GMC SONOMA

Typical onset: 80,000-130,000 mi

Symptoms: Coolant loss with no visible external leaks, White exhaust smoke on cold start, Milky oil on dipstick or oil cap, Overheating or rough idle when warm

Fix: Replace lower intake manifold gaskets and resurface mating surfaces. Often discover cracked distributor housing or warped intake from overheating. Budget 6-8 labor hours. If coolant mixed with oil long enough, expect bearing damage requiring full rebuild.

Estimated cost: $800-1,400

Typical onset: 90,000-140,000 mi

Symptoms: Chronic overheating under load, Coolant disappearing into combustion chambers, Pressure in cooling system, burping radiator cap, Exhaust gases in coolant (bubbles in overflow tank)

Fix: The 2.2L is notorious for blown head gaskets, often warping the head in the process. Machine work or head replacement required, plus timing chain components while you're in there. 10-14 labor hours. Many owners just swap in a junkyard engine instead of rebuilding.

Estimated cost: $1,200-2,200

Typical onset: 70,000-120,000 mi

Symptoms: Trans fluid dripping at radiator connections, Low fluid level causing delayed engagement or slipping, Pink fluid puddles under front of truck

Fix: Steel cooler lines rust at quick-disconnect fittings where they enter the radiator. Replace both lines and flare-nut fittings. If fluid ran low before discovery, expect clutch pack damage inside transmission. Lines alone are 2-3 hours; if trans rebuild needed, add $1,500-2,500.

Estimated cost: $250-450

Typical onset: 60,000-110,000 mi

Symptoms: ABS light stays on constantly, No rear ABS function, rear wheels lock easily on wet pavement, Intermittent ABS light with grinding noise from rear differential

Fix: Early RABS modules corrode internally and sensor wiring chafes at rear axle. Scan for codes first—often just a sensor replacement (1 hour), but module failures require parts that are increasingly hard to source. Many owners just disable the system and live without rear ABS.

Estimated cost: $150-600

Typical onset: 100,000-150,000 mi

Symptoms: Hard starting when engine is hot, Rough idle, hesitation, and misfires across multiple cylinders, Fuel smell in oil or visible fuel in intake plenum, Check engine light with lean/rich codes on multiple banks

Fix: The Central Sequential Fuel Injection 'spider' unit under the intake plenum develops leaking poppet valves that dump raw fuel into cylinders. Requires intake removal and replacement with updated CSFI or MPFI retrofit kit. 5-7 labor hours. Fuel-diluted oil destroys bearings if driven long enough.

Estimated cost: $700-1,200

Symptoms: Visible rust-through at rear cab corners above bed, Frame surface rust at body mounts and rear leaf spring hangers, Sagging bed caused by rusted bed mounts

Fix: Salt-belt trucks develop severe cab corner and rocker rust, plus frame rot at rear crossmember and spring hangers. Cosmetic cab corner patches run 4-6 hours bodywork. Structural frame repair varies wildly—light surface work to full section replacement. Inspect before purchase; many are too far gone to justify repair.

Estimated cost: $500-3,000