1994 OLDSMOBILE CUTLASS SUPREME

Typical onset: 60,000-120,000 mi

Symptoms: White exhaust smoke on startup, Coolant mysteriously disappearing with no visible leaks, Milky oil or coolant in oil pan, Rough idle and eventual engine knock from bearing damage

Fix: The Dex-Cool plastic gasket deteriorates and allows coolant into the crankcase. If caught early (just gaskets), it's 6-8 hours labor for upper and lower intake gaskets. If coolant sat in the oil for weeks, you're looking at bearings, possibly pistons, or complete engine rebuild. We see full rebuilds on about 40% of these failures because owners ignored early symptoms. Short block swap is 18-22 hours.

Estimated cost: $800-1,200 (gaskets only) or $2,800-4,500 (full rebuild/short block)

Typical onset: 80,000-150,000 mi

Symptoms: Transmission fluid in coolant reservoir (strawberry milkshake appearance), Coolant in transmission pan, Erratic shifting or complete transmission failure, Pink foam under radiator cap

Fix: Steel cooler lines rust through at the radiator connection, or the internal radiator cooler fails. Coolant mixes with ATF and destroys clutch packs and pump seals. Requires radiator replacement, cooler line replacement, transmission flush minimum—but if driven after contamination starts, full transmission rebuild. Trans rebuild on 4T60-E is 12-16 hours, plus radiator work adds 3 hours.

Estimated cost: $400-700 (early catch, flush and radiator) or $1,800-2,800 (transmission rebuild)

Typical onset: 100,000-180,000 mi

Symptoms: External coolant leaks from head/block mating surface, Overheating without visible coolant loss, Compression loss in one or more cylinders, Combustion gases in cooling system (bubbling reservoir)

Fix: Usually the result of previous overheating from intake gasket neglect. Both heads come off—figure 10-14 hours labor. Critical to check head flatness; warped heads need machining ($120-180 each). If you're this deep, replace intake gaskets simultaneously or you'll be back in six months.

Estimated cost: $1,400-2,200

Typical onset: 70,000-130,000 mi

Symptoms: Severe clunk when shifting from Park to Drive or Reverse, Engine rocks excessively during acceleration, Vibration at idle that smooths out at higher RPM, Visible torn rubber or fluid leaking from mount

Fix: The hydraulic transmission mount deteriorates and either leaks fluid or tears completely. It's a 2-3 hour job requiring partial cradle drop or support of the powertrain. Not urgent but contributes to driveline wear if ignored. OEM mounts last longer than aftermarket—spend the extra $40.

Estimated cost: $250-450

Typical onset: 90,000-160,000 mi

Symptoms: No-start condition with crank but no fire, Stalling at operating temperature, Fuel gauge reads empty when tank is full (sending unit), Whining noise from rear seat area

Fix: The in-tank pump wears out, often taking the fuel filter sock and sending unit with it. Tank must be dropped—3.5-4.5 hours labor. Always replace the strainer and check fuel pressure regulator while you're in there. Running the tank near empty repeatedly accelerates pump death.

Estimated cost: $450-750

Typical onset: Any mileage (heat-related)

Symptoms: Random no-start when engine is hot, Stalling after highway driving, Starts fine when cold, fails after 20+ minutes of driving, No Check Engine light in many cases

Fix: Heat causes internal sensor failure. It's behind the harmonic balancer—looks easy but requires balancer removal. 2-3 hours labor. The OEM AC Delco sensor is mandatory; cheap parts store replacements fail within months. This one stumps a lot of DIYers because it's intermittent and doesn't always throw a code.

Estimated cost: $200-380