1973 MERCURY MARQUIS

Typical onset: 80,000-150,000 mi or 40+ years regardless of miles

Symptoms: Rattling or slapping noise from front of engine on cold start, Rough idle, poor performance, backfiring through carburetor, Check timing and it's retarded 10-15 degrees despite setting distributor correctly, Won't pass emissions or runs rich constantly

Fix: Replace timing chain, gears, and tensioner. Nylon-toothed cam gears were used through early '70s and disintegrate with age. Job requires pulling radiator, harmonic balancer, timing cover. 6-8 hours labor for competent shop. Use double-roller steel chain set, not OEM-style nylon.

Estimated cost: $800-1,400

Symptoms: Visible rust perforation on frame rails behind front wheels and ahead of rear axle, Body sags or lists to one side when parked, Doors don't close properly or require lifting to latch, Creaking, popping sounds over bumps from body mounts

Fix: Requires lift inspection of entire frame. Body mounts (rubber biscuits) rot out and need replacement. Frame rust may require sectioning and welding if structural. Body mount job alone is 4-6 hours; frame repair can be 20+ hours depending on severity. Many survivors from rust belt states are terminal cases.

Estimated cost: $600-1,200 for mounts only; frame work $2,000-5,000+

Typical onset: 100,000-140,000 mi

Symptoms: No forward gears (1st, 2nd, Drive), reverse works fine, Slipping in Drive, especially under load or when warm, Delayed engagement into Drive, loud clunk when shifting, Burnt transmission fluid smell

Fix: C6 three-speed automatic is generally bulletproof but forward clutch pack wears with high mileage or overheating. Requires transmission removal and rebuild. 8-10 hours R&R plus rebuild cost. Often find worn intermediate servo and bands during teardown.

Estimated cost: $1,800-2,800

Typical onset: 60,000+ mi or age-related seal failure

Symptoms: Fluid leaking from steering box (driver side frame rail), Excessive play in steering wheel (more than 2 inches before wheels respond), Wandering on highway, constant steering corrections needed, Groaning or whining when turning at low speeds

Fix: Ford integral power steering boxes develop internal wear and seal leaks. Rebuild kits available but labor-intensive (6-8 hours); most shops recommend reman unit swap. Requires pitman arm puller, alignment afterward. Check pump and hoses too—often they're original and cracked.

Estimated cost: $600-1,100

Symptoms: Hard starting or won't start after sitting weeks or months, Runs rough, stumbles on acceleration, dies at idle, Gas smell from carb overflow or tank venting, Fuel gauge reads erratic or stuck

Fix: Motorcraft/Autolite 2150 or 4300-series carbs gum up from ethanol fuel and sitting. Needs complete disassembly, ultrasonic cleaning, rebuild kit. Also replace fuel filter, check fuel pump diaphragm, and inspect rubber fuel lines—they crack with age. Sending unit floats corrode. 4-6 hours for thorough carb rebuild and fuel system service.

Estimated cost: $400-750

Typical onset: 70,000-120,000 mi

Symptoms: Clunking over bumps from front suspension, Steering wander, uneven tire wear on inside edge, Visible up-down play when prying on front tire at 6 and 12 o'clock, Grease boot torn or missing, joint dry

Fix: Ford's twin I-beam front end uses wear-prone ball joints. Uppers fail more often. Requires press or ball joint service kit, alignment mandatory after. Do both sides and inspect spindle bearings while apart. 5-7 hours for both sides including alignment.

Estimated cost: $700-1,200

Typical onset: 80,000+ mi or age-related seal failure

Symptoms: Brake pedal slowly sinks to floor when holding at stop, Low or spongy pedal feel even after bleeding, Brake fluid leaking at firewall or inside booster, Rear brakes lock up prematurely or pull to one side

Fix: Single-reservoir master cylinders leak internally with age. Rear drums often have glazed shoes or leaking wheel cylinders. Front discs usually okay. Replace master, inspect/replace wheel cylinders, turn drums if within spec. Power booster may also need replacement if leaking vacuum. 4-6 hours total for complete brake overhaul.

Estimated cost: $500-900