1992 PONTIAC BONNEVILLE

Typical onset: 80,000-130,000 mi

Symptoms: sudden loss of power under boost, metallic knocking from bottom end, oil consumption spiking before failure, catastrophic engine seizure or rod through block

Fix: The Series I supercharged engine has weak hypereutectic pistons that crack skirts or collapse ring lands, often taking out cylinder walls. Requires complete engine rebuild with forged pistons or short block replacement. 18-24 hours labor for proper rebuild with machine work.

Estimated cost: $3,500-6,000

Typical onset: 70,000-120,000 mi

Symptoms: pink milkshake in coolant reservoir, transmission slipping or no forward gears, engine overheating combined with transmission problems, coolant in transmission pan

Fix: The internal transmission cooler in the radiator fails, allowing coolant and ATF to mix. This destroys the 4T60-E transmission within miles if not caught immediately. Requires radiator replacement, complete transmission flush or rebuild, and all cooler lines. Subject of NHTSA recall but many not repaired. 12-16 hours if transmission needs rebuild.

Estimated cost: $2,000-4,500

Typical onset: 60,000-100,000 mi

Symptoms: severe clunking when shifting into drive or reverse, engine rocking excessively during acceleration, vibration at idle in gear, visible engine sag on passenger side

Fix: The front and side transmission mounts fail from oil contamination and age. Front mount requires subframe support and is labor-intensive on this FWD platform. 3-4 hours for both mounts.

Estimated cost: $400-700

Typical onset: 90,000-150,000 mi

Symptoms: supercharger whine disappears suddenly, loss of boost pressure, check engine light with rich/lean codes, rubber dust in intake

Fix: The rubber coupler between supercharger and snout wears and can shred, causing loss of boost. Earlier problem on Series I than later Series II engines. Requires supercharger removal and coupler replacement. 4-5 hours labor.

Estimated cost: $500-900

Typical onset: 100,000-140,000 mi

Symptoms: external coolant leaks from head/block junction, white smoke from exhaust, coolant loss with no visible leaks, overheating under load

Fix: The supercharged engine runs higher cylinder pressures and can blow head gaskets, especially if cooling system maintenance was deferred. Requires both heads pulled, resurfaced, new gaskets, and all cooling system components inspected. 12-14 hours labor.

Estimated cost: $2,200-3,500

Typical onset: 80,000-130,000 mi

Symptoms: ABS light on constantly, grinding noise from ABS unit under hood, extended brake pedal travel, loss of ABS function but brakes still work

Fix: The Bosch ABS pump motor fails, usually requiring complete unit replacement as rebuilds are uncommon. Base braking still functions. 2-3 hours with brake bleeding.

Estimated cost: $800-1,400