1974 BMW 2002 TURBO

Typical onset: varies widely - often from abuse at any mileage

Symptoms: Knocking or pinging under boost, Excessive blue smoke from exhaust, Loss of compression in one or more cylinders, Wastegate actuator rod disconnected or poorly adjusted

Fix: The original wastegate setup is primitive and many cars have been modified or are running 10+ psi instead of the stock 7 psi, leading to detonation and cracked ring lands. Fixing blown pistons means complete engine-out teardown, bore inspection, proper piston sourcing (correct 8.5:1 CR turbo pistons are rare), and careful wastegate calibration. Expect 25-35 hours labor for a proper rebuild with machine work.

Estimated cost: $6,500-12,000

Typical onset: 50,000-90,000 mi or after repeated overheating

Symptoms: Coolant loss with no visible leaks, White smoke from exhaust on cold start, Oil in coolant or coolant in oil, Rough idle and misfires

Fix: The M10 head gasket doesn't love boost pressure and heat cycling. Head removal, resurfacing (often warped 0.003-0.008 inches), and proper torque sequence with ARP studs recommended. Critical to check head flatness and block deck. 12-16 hours labor plus machine shop time.

Estimated cost: $2,200-3,800

Typical onset: 80,000-120,000 mi

Symptoms: Clutch pedal feel changes or excessive free play, Metallic knocking when clutch is depressed or released, Visible crankshaft endplay beyond 0.003-0.011 inch spec, Oil pressure drop at idle

Fix: Hard clutch engagement and aggressive driving wear the center main thrust surfaces. Requires crank removal, inspection for scoring, possible machine work or replacement crank (expensive and hard to source). Often discovered during engine rebuild. 20-28 hours for engine-out crank R&R with bearing replacement.

Estimated cost: $4,500-7,500

Typical onset: not mileage-specific - age and ethanol damage

Symptoms: Hard starting when hot, Rough idle and hesitation, Fuel leaks at pump or injector lines, Rich running and black exhaust smoke

Fix: The mechanical Kugelfischer injection pump has internal seals that dry out and plungers that wear. Ethanol fuel destroys original rubber components. Very few shops rebuild these correctly - often requires specialist service or sourcing rebuilt unit from Europe. Injectors also need ultrasonic cleaning and flow-testing. 8-12 hours removal, install, and tuning if you have a good core to swap.

Estimated cost: $2,800-5,500

Typical onset: 60,000-100,000 mi

Symptoms: Clunking when shifting or on/off throttle transitions, Excessive shifter vibration, Whining noise in neutral that goes away with clutch depressed, Difficult engagement into first or reverse

Fix: Transmission mounts rot out on all these cars - rubber degrades after 50 years. Input shaft bearing wears from clutch riding and aggressive launches. Mount replacement is straightforward (2-3 hours), but bearing replacement requires transmission removal and partial disassembly. Full trans rebuild often makes sense at this point given age. 14-18 hours for complete manual rebuild.

Estimated cost: $400-800 for mount only, $2,500-4,200 for trans rebuild

Typical onset: 70,000+ mi or long storage periods

Symptoms: Blue smoke on startup that clears after 30 seconds, Oil consumption 1 quart per 500-800 miles, Spark plugs oil-fouled on intake side, Smoke during deceleration after highway cruise

Fix: Original valve seals get hard and brittle. Can be replaced with head on car using compressed air method in 6-8 hours, but most techs pull the head for full valve job and inspection given the age. Good opportunity to lap valves, check guides, and replace all seals correctly. 10-14 hours for complete valve job with head R&R.

Estimated cost: $1,800-3,200