2003 CHEVROLET TRAILBLAZER

Typical onset: 100,000-150,000 mi

Symptoms: sudden loss of oil pressure, knocking/ticking from bottom end, oil consumption before failure, metal shavings in oil, check engine light with low oil pressure codes

Fix: Complete engine replacement or rebuild required. Lower end bearings fail due to oiling system inadequacies and sludge buildup. Connecting rod and main bearings spin, requiring full teardown. Expect 18-25 labor hours for in-frame rebuild, 12-16 hours for used engine swap.

Estimated cost: $3,500-6,500

Typical onset: 80,000-120,000 mi

Symptoms: pink milkshake in coolant reservoir, transmission slipping or erratic shifts, engine overheating, coolant loss with no external leaks, transmission fluid in radiator

Fix: Internal radiator transmission cooler fails, mixing coolant and ATF. Requires radiator replacement, external cooler installation, transmission flush or rebuild if contamination circulated long. Transmission damage common if caught late. 4-6 hours if transmission survives, 12-18 hours if rebuild needed.

Estimated cost: $800-1,200 (cooler fix only), $2,500-4,000 (with transmission rebuild)

Typical onset: 90,000-140,000 mi

Symptoms: clunking during turns, grinding noise from front end, fluid pooling under front axle, vibration at highway speeds, whining that increases with speed

Fix: Pinion seal or carrier bearings fail on front diff. If caught early, seal replacement is 2-3 hours. If bearings are damaged, full differential overhaul required at 6-8 hours labor.

Estimated cost: $400-700 (seal only), $1,200-1,800 (bearing overhaul)

Typical onset: 120,000-180,000 mi

Symptoms: no start condition, stalling at idle or under load, extended cranking before start, loss of power at highway speeds, check engine light with low fuel pressure codes

Fix: In-tank fuel pump assembly fails. Requires dropping fuel tank for access. 3-4 hours labor. Common enough to be considered a wear item on high-mileage examples.

Estimated cost: $600-900

Typical onset: 70,000-110,000 mi

Symptoms: growling or humming that increases with speed, noise changes when turning, ABS light illuminated, vibration through steering wheel, excessive wheel play

Fix: Hub bearing assemblies wear prematurely, especially with 4WD use or aggressive driving. Bolt-on hub assembly makes replacement straightforward. 1.5-2 hours per side.

Estimated cost: $300-500 per wheel

Typical onset: 90,000-130,000 mi

Symptoms: coolant seepage at rear of engine, rough idle when cold, slight coolant loss over time, possible misfire codes, coolant smell from vents

Fix: Plastic intake manifold gaskets deteriorate. Not as catastrophic as Dexcool era GM V6/V8 issues but still requires manifold removal. 4-6 hours labor.

Estimated cost: $500-800

Symptoms: HVAC blower only works on high speed, intermittent blower operation, no air flow on lower speeds, blower cuts in and out

Fix: Resistor module behind glove box fails frequently. Simple fix, 0.5-1 hour labor, but owners see it multiple times over vehicle life.

Estimated cost: $150-250

Typical onset: 80,000-120,000 mi

Symptoms: clunking over bumps, wandering steering, uneven tire wear, vibration through steering wheel, visible play when jacking front end

Fix: Upper and lower ball joints wear, especially with off-road use. Critical safety item. Both uppers and lowers typically done together. 4-5 hours for both sides with alignment.

Estimated cost: $800-1,200