1976 CADILLAC ELDORADO

Typical onset: 60,000-100,000 mi

Symptoms: Severe clunking on acceleration or deceleration, Visible powertrain sag when viewed from side, Shifter vibration at idle, Driveline angle changes causing CV joint wear

Fix: Rubber mounts deteriorate and the transaxle literally drops. Requires lifting powertrain to replace mounts and cradle bushings. 6-8 hours labor because access is terrible with FWD packaging.

Estimated cost: $800-1,400

Typical onset: 50,000-120,000 mi

Symptoms: ATF puddles under front of car, Pink fluid mixing with coolant in radiator, Transmission overheating and slipping, Sudden loss of all transmission fluid

Fix: Steel lines rust through where they run along subframe, and internal radiator cooler can rupture mixing ATF with coolant (kills transmission fast). External lines are 3-4 hours, internal cooler failure means radiator replacement plus transmission flush, 5-7 hours total.

Estimated cost: $600-1,800

Typical onset: 80,000-140,000 mi

Symptoms: Blue smoke on startup and acceleration, Oil consumption exceeding 1 qt per 500 miles, Loss of compression and power, Blowby visible at oil filler cap

Fix: Soft pistons and rings were an EPA-era compromise that wear prematurely. Full rebuild with modern ring pack and possibly bore/hone runs 35-45 hours because engine stays in car but everything comes off from above. Expect machine shop work.

Estimated cost: $3,500-5,500

Typical onset: 100,000-150,000 mi

Symptoms: Deep knocking from bottom end, especially when cold, Oil pressure drops below 10 psi at idle when hot, Metallic debris in oil filter, Rod knock that worsens with RPM

Fix: The 500 has generous bearing clearances that get worse with wear, and oil starvation happens if maintenance was deferred. Full bottom-end rebuild requires engine removal in most cases despite FWD orientation. 40-55 hours with crank grinding.

Estimated cost: $4,000-6,500

Typical onset: 70,000-110,000 mi

Symptoms: Coolant loss with no visible leaks, White smoke from exhaust, Milky oil on dipstick, Overheating and rough idle

Fix: Cast iron heads on aluminum-composition gaskets from this era fail, often both banks simultaneously. Heads need to be checked for warpage and possibly milled. 18-24 hours labor with both banks.

Estimated cost: $2,200-3,500

Symptoms: Hard starting when hot, Stumbling and stalling at idle, Hesitation on acceleration, Won't restart after short stops

Fix: Old fuel varnishes the carb and clogs the sock filter in the tank. These cars sit a lot. Inline filter is easy (1 hour), but if tank needs dropping and cleaning add 4-5 hours. Carb rebuild adds another 6-8 hours if you do it right.

Estimated cost: $150-1,200