2009 PONTIAC MONTANA

Typical onset: 80,000-140,000 mi

Symptoms: Loss of coolant with no visible leaks, White smoke from exhaust, Oil contaminated with coolant (milky dipstick), Rough idle and misfires, Complete engine seizure in severe cases

Fix: Intake manifold gasket failure dumps coolant into cylinders, washing cylinder walls and destroying bearings. By the time symptoms show, damage is done—head gaskets, piston rings, bearings all need replacement. Most shops quote engine rebuild (40-50 hours) or used engine swap (15-20 hours). Preventive gasket replacement around 60k-80k can save the engine.

Estimated cost: $3,500-6,500

Typical onset: 70,000-120,000 mi

Symptoms: Pink milkshake appearance in coolant reservoir, Transmission slipping or delayed engagement, Engine overheating, Coolant smell from transmission dipstick, Catastrophic transmission failure if driven after mixing

Fix: Internal radiator transmission cooler develops pinhole leak, mixing ATF and coolant. Requires radiator replacement, external trans cooler installation, complete fluid flush of both systems (8-12 hours). If driven after contamination starts, transmission internals are damaged—add rebuild or replacement (15-20 hours total).

Estimated cost: $800-1,200 (caught early), $2,800-4,500 (with trans damage)

Typical onset: 60,000-100,000 mi

Symptoms: Coolant loss with no external puddles, Sweet smell from exhaust, White residue around intake manifold, Overheating under load, Check engine light with misfire codes

Fix: Dexcool-era composite gaskets deteriorate, leaking coolant externally or internally. Caught early, it's gasket replacement only (6-8 hours including intake removal, cleaning, new gaskets, coolant flush). Delayed repairs lead to the catastrophic engine failure described above.

Estimated cost: $600-1,100

Typical onset: 80,000-130,000 mi

Symptoms: Clunk when shifting from Park to Drive/Reverse, Excessive vibration at idle, Visible engine/trans movement when accelerating, Rubbing noise from engine bay over bumps

Fix: Hydraulic transmission mount fails, allowing excessive powertrain movement. Replacement is straightforward (1.5-2 hours) but requires supporting engine/trans weight. Often discovered during other work. Replace all motor mounts if budget allows—they fail in sequence.

Estimated cost: $200-350

Typical onset: 120,000-180,000 mi

Symptoms: Harsh 1-2 or 2-3 shifts, Slipping under acceleration, No reverse or specific gear, Burnt ATF smell, Whining noise increasing with speed

Fix: Even without cooler contamination, the 4T65-E develops valve body issues, clutch pack wear, and torque converter problems. Rebuild requires 12-16 hours; most shops recommend remanufactured unit (8-10 hours swap). Fluid changes every 50k help but don't prevent eventual failure.

Estimated cost: $2,200-3,800

Typical onset: 100,000-150,000 mi

Symptoms: No-start or extended cranking when hot, Stumbling/hesitation during acceleration, Engine dies at highway speeds, Fuel gauge erratic or stuck, Whining from fuel tank

Fix: Fuel pump assembly fails, often intermittently at first. Requires dropping fuel tank or removing rear seats for access (2.5-3.5 hours). Use OE-quality pump—cheap aftermarket units fail quickly on these vans.

Estimated cost: $450-750