1981 OLDSMOBILE CUTLASS

Typical onset: 80,000-120,000 mi

Symptoms: Rattling noise on cold startup that disappears when warm, Engine timing retarded causing poor performance and fuel economy, Check engine light or timing codes, Hard starting especially when hot

Fix: GM used nylon-coated timing gears that shed their teeth over time. Requires front cover removal, new timing set with steel gears, and often new oil pump and front seal while you're in there. 6-8 hours labor for proper job with gaskets and seals.

Estimated cost: $800-1,400

Typical onset: 60,000-90,000 mi

Symptoms: Excessive white or blue smoke, Head gasket failure, Cracked cylinder heads, Catastrophic block failure, Coolant in oil or vice versa

Fix: The 260 diesel (LF9) is essentially a converted gas engine with insufficient block strength. Head bolt failures and cracked blocks are endemic. Most owners convert to gas 305 or 350 (20-30 hours including all new mounts, exhaust, wiring, fuel system). Rebuilding the diesel is throwing good money after bad.

Estimated cost: $3,500-6,000

Symptoms: Rough idle and stalling, Flooding or fuel leaking from carb, Hesitation on acceleration, Black smoke from rich mixture, Poor fuel economy

Fix: The Q-jet is a good carb when properly maintained, but 40+ year old examples have worn throttle shafts, hardened accelerator pump diaphragms, and clogged passages. Professional rebuild with quality kit runs 3-4 hours. Many shops just swap on a remanufactured unit.

Estimated cost: $400-750

Symptoms: Check engine light stuck on, Poor driveability and surging, Mixture control solenoid clicking excessively, Failed oxygen sensor causing rich running, Vacuum hose deterioration affecting sensors

Fix: Early GM computer controls are primitive and troublesome. Oxygen sensors fail, ECM units corrode (especially in humid climates), and the maze of vacuum lines gets brittle. Diagnosis takes 1-2 hours, repairs vary widely. Many owners delete emissions equipment where legal.

Estimated cost: $200-900

Typical onset: 60,000-100,000 mi

Symptoms: Slipping between gears especially 1-2 shift, No reverse or weak reverse, Burnt transmission fluid, Delayed engagement when shifting to drive

Fix: The TH200 (sometimes called THM200) is an undersized lightweight transmission prone to clutch pack and band failure. Rebuild runs 8-12 hours, but many shops recommend upgrading to a TH350 swap for reliability (12-15 hours including custom driveshaft).

Estimated cost: $1,800-2,800

Symptoms: Body sits crooked on frame, Doors don't close properly, Visible rust through on rocker panels and rear quarters, Floor pan rust-through, Frame rail perforation behind rear axle

Fix: G-bodies rust aggressively in the salt belt. Body mounts rot out (8 total), frame rails perforate, and floor pans dissolve. Body mount replacement is 4-6 hours if frame is solid. Severe frame rust means the car is effectively totaled. Always inspect underneath before purchase.

Estimated cost: $600-1,200

Typical onset: 100,000+ mi

Symptoms: Oil dripping from bell housing area, Oil spots under rear of engine, Clutch contamination on manual transmission models, Low oil level between changes

Fix: Classic GM rope-style rear main seal eventually starts seeping. Requires transmission removal to replace properly (6-8 hours on V8s). Many owners just keep adding oil unless it's severe. Not a breakdown issue but messy and wasteful.

Estimated cost: $500-900