1996 MITSUBISHI DIAMANTE

Typical onset: 80,000-140,000 mi

Symptoms: Rapid oil consumption (quart per 500-800 miles), Ticking/knocking from valvetrain that progresses to rod knock, Oil pressure warning light flickering at idle, White smoke from exhaust (coolant burning through porous block), Milky oil or coolant loss with no visible leaks

Fix: The 6G72 suffers from factory oil passage restrictions and porous cast blocks that allow coolant seepage into cylinders. Sludge clogs oil pickups leading to bearing starvation. Fix requires full engine rebuild (pistons, rings, bearings, head gaskets) or used engine swap. Expect 18-25 labor hours for rebuild, 10-14 for swap.

Estimated cost: $3,200-5,800

Typical onset: 90,000-150,000 mi

Symptoms: ATF dripping from radiator area or pooling under engine bay, Transmission slipping or delayed engagement when hot, Pink ATF mixing with coolant in overflow reservoir, Overheating transmission temp gauge reading high

Fix: Steel cooler lines rust through where they pass along subframe. Internal radiator ATF cooler can also fail, contaminating coolant. Replace lines, external cooler, and flush both systems. If coolant entered trans, overhaul required. 3-4 hours for lines/cooler only, add 12-18 if trans needs rebuild.

Estimated cost: $450-850 (lines/cooler only), $2,200-3,500 (with trans rebuild)

Typical onset: 110,000-160,000 mi

Symptoms: Overheating with no external coolant leaks, White exhaust smoke and sweet smell, Bubbles in coolant reservoir when running, Rough idle and misfires on multiple cylinders, Oil contamination in coolant or vice versa

Fix: V6 configuration means both banks typically need work simultaneously. Must resurface heads, replace gaskets, timing belt/water pump while apart. Check for block porosity—if present, not worth fixing. 14-18 labor hours including timing components.

Estimated cost: $2,800-4,200

Typical onset: 70,000-120,000 mi

Symptoms: Severe clunk when shifting from Park to Drive or Reverse, Vibration through floor at idle in gear, Excessive engine movement visible when accelerating, Transmission shifter feels loose or imprecise

Fix: Hydraulic transmission mount fails internally, allowing excessive drivetrain movement. Common wear item but annoying. Replace mount—straightforward job. 1.5-2.5 hours.

Estimated cost: $280-450

Typical onset: 60,000-100,000 mi

Symptoms: Hesitation or stumble during acceleration, Engine stalling at idle after driving, Difficulty starting when fuel tank below half, Loss of power climbing hills or under load

Fix: In-tank sock filter and inline filter clog from varnish buildup if fuel isn't changed regularly. Restricted flow kills fuel pump prematurely. Replace both filters and pump if pressure test fails. 2-3 hours for filters, add 2 hours for pump.

Estimated cost: $320-580 (filters + pump if needed)

Typical onset: 100,000-150,000 mi

Symptoms: Deep knocking sound from lower engine that worsens with RPM, Metal shavings in oil during changes, Low oil pressure at operating temp, Rattling on cold starts that doesn't go away

Fix: Sludge-related oil starvation scores crank journals and spins bearings. Requires crank removal, machining/replacement, new bearings, full bottom-end rebuild. At this point, short block replacement or used engine more cost-effective. 20-28 hours for full crank job.

Estimated cost: $3,800-6,200