1994 JEEP WRANGLER

Typical onset: 80,000-150,000 mi

Symptoms: White smoke from exhaust, especially cold start, Coolant loss with no visible leaks, Milky oil on dipstick or cap, Overheating and rough idle

Fix: The 0331 casting head (1999-2001 mostly, but some '94s got early batches) cracks between cylinders 3-4. Even non-0331 heads blow gaskets from overheating. Requires head removal, machining or replacement, new gasket set. 8-12 labor hours if you catch it early; full rebuild if it ran hot too long.

Estimated cost: $1,200-2,800

Typical onset: 90,000-130,000 mi

Symptoms: No-start condition, cranks but won't fire, Intermittent stalling at operating temperature, Whining noise from rear when key is on, Loss of power under load

Fix: In-tank pump dies from heat and ethanol fuel. Drop the tank (2.5 hours), replace pump module and filter sock. The YJ recall for pump wiring harness chafing compounds this—check for melted connectors at the pump. Always replace fuel filter at same time.

Estimated cost: $400-700

Typical onset: 70,000-120,000 mi

Symptoms: Clunking when shifting or engaging clutch, Excessive driveline vibration, Shifter slop or difficulty finding gears, Visible sag of transmission tailhousing

Fix: The rubber transmission mount collapses, letting the tailhousing droop and stress the bellhousing. Aluminum AX-5 bellhousings crack around the bolt holes. Mount is 1 hour; bellhousing crack requires transmission removal and welding or replacement case (6-8 hours). Catch the mount early to prevent cracking.

Estimated cost: $120-180 (mount only), $800-1,400 (cracked bellhousing)

Symptoms: Visible rust perforation in rear frame rails, Soft or flaking metal at body mount points, Floor pan rust-through under carpet, Rear spring hangers separating from frame

Fix: YJs rust badly in the Northeast and Midwest—rear frame rails, floor pans, and tailgate corners are terminal if neglected. Frame repair requires cutting and welding in new sections (12-20 hours). Body tubs are available but expensive. If frame is compromised at spring mounts, walk away—not economical to fix.

Estimated cost: $1,500-4,000+ depending on extent

Typical onset: 100,000-160,000 mi

Symptoms: Loud knocking from lower engine, worsens with RPM, Metal shavings in oil, Low oil pressure at idle, Sudden catastrophic failure / locked engine

Fix: The 2.5L is less robust than the 4.0L—rod bearings spin from oil starvation or extended oil change intervals. Once knocking starts, it's too late. Requires short block replacement or full rebuild. 16-20 hours labor. Many owners swap in a 4.0L instead for similar cost.

Estimated cost: $2,500-4,500

Typical onset: 60,000-140,000 mi

Symptoms: Rough idle, hunting RPM at stops, Hesitation or stumble on acceleration, Check Engine Light with codes P0122 / P0123, Stalling when coming to a stop

Fix: TPS wears out on the throttle body; vacuum lines crack and leak. Diagnose with a scan tool and vacuum gauge. TPS replacement is 0.5 hours; chasing vacuum leaks (intake manifold gasket, brake booster line) adds 1-2 hours. Often misdiagnosed as fuel delivery.

Estimated cost: $150-400

Typical onset: 80,000-150,000 mi

Symptoms: Intermittent no-start, especially when hot, Engine cranks but no spark or fuel pump signal, Stalling while driving, restarts after cooling, No tachometer reading during crank

Fix: The CPS on the bellhousing fails from heat cycles. It's a $40 part and 0.5 hours labor, but it strands you. Always carry a spare. Some techs see corrosion in the connector—clean and dielectric grease it during replacement.

Estimated cost: $80-150