1966 PONTIAC TEMPEST

Typical onset: 70,000-120,000 mi (original units)

Symptoms: Slipping between gears, especially 1st to 2nd, Transmission fluid discolored or burnt smell, Harsh or delayed engagement when shifting into drive, Overheating after highway use—oil cooler lines often corroded through

Fix: Full rebuild or replacement. Trans R&R is 6-8 hours, rebuild adds another 12-16 hours if farmed out. Original cooler lines rust from inside out—replace during any trans work. Expect 18-24 total labor hours for complete job.

Estimated cost: $2,200-3,800

Typical onset: 80,000-140,000 mi

Symptoms: Deep knocking sound from crankcase, worse under load, Metal shavings in oil or on magnetic drain plug, Low oil pressure at idle (under 10 psi hot), Sudden catastrophic failure if bearings spin

Fix: Engine must come out for proper access—10-12 hours R&R. If caught early, bearing replacement and crank polish runs 16-20 hours total. If crank is scored or out of spec, you're looking at machine shop work (grind or replacement) adding $400-800 and another week. Many owners opt for short block swap at this point.

Estimated cost: $2,800-5,500

Typical onset: 90,000-150,000 mi

Symptoms: Blue smoke on startup or during deceleration, Excessive oil consumption (more than 1 qt per 500-800 miles), Poor compression readings across multiple cylinders, Crankcase pressure pushing oil past valve cover gaskets

Fix: Requires cylinder honing at minimum, often a full rebore if taper exceeds .010". New pistons and rings, plus decking—20-28 hours total with machine work turnaround. If cam or lifters are suspect (common at this age), do them simultaneously. Engine must be pulled.

Estimated cost: $3,200-5,800

Symptoms: Clunking when shifting from park to drive or reverse, Excessive driveline vibration at highway speeds, Visible sagging or torn rubber in transmission mount, Transmission tail housing sits low or contacts crossmember

Fix: Mount replacement is straightforward—2-3 hours with proper jackstands to support transmission. Crossmember rust is the real issue; inspect carefully for stress cracks or rot-through. Crossmember replacement adds another 2-4 hours depending on fastener condition.

Estimated cost: $180-450

Symptoms: Hard starting after sitting, especially when hot, Fuel smell in garage or around tank, Stalling or stumbling under acceleration, Visible corrosion or weeping at fuel line connections

Fix: Original steel fuel lines rust from inside out, and rubber hoses turn to concrete. Tank often has varnish or rust internally. Complete fuel system overhaul: tank drop and clean/replace (4-6 hours), new lines (3-5 hours), filter, pump check. Mechanical pumps usually still work but diaphragms can fail.

Estimated cost: $650-1,400

Typical onset: 60,000+ mi

Symptoms: Oil seeping from front of engine below water pump, Wobbling harmonic balancer visible at idle, Squealing or chirping from accessory belt area, Timing cover gasket weeping oil onto crossmember

Fix: Balancer replacement requires puller and installer—2-3 hours. Timing cover reseal while you're in there adds 1-2 hours (drain coolant, pull radiator for access). These I6 engines are reliable but front seal access is tight. Do water pump at same time if original.

Estimated cost: $380-750