1972 BMW 1600

Typical onset: 80,000-150,000 mi (often unknown actual mileage)

Symptoms: Deep knocking on cold start that quiets when warm, Low oil pressure below 20 psi at idle when hot, Metallic rattling under load, Metal shavings in oil filter

Fix: Engine needs to come out for proper bearing replacement. Expect 20-25 hours for engine R&R, disassembly, measuring crank journals, installing bearings, and reassembly. Most shops recommend full lower end refresh including thrust washers and oil pump while you're in there.

Estimated cost: $3,500-6,000

Typical onset: 100,000-180,000 mi

Symptoms: Blue smoke on deceleration, Excessive crankcase pressure, oil in air cleaner, Oil consumption over 1 qt per 500 miles, Poor compression readings below 120 psi

Fix: Requires engine removal and either bore/hone with standard oversized pistons or sleeving if already at max oversize (.040). Figure 25-30 hours for full top-end rebuild including valve job. Many owners opt for complete engine rebuild at this point since it's already apart.

Estimated cost: $4,000-7,500

Symptoms: Excessive drivetrain clunk on engagement, Shifter vibration at highway speed, Visible transmission sag when inspected from below, Difficult shifting into first and reverse

Fix: Rubber mounts deteriorate and the sheet metal crossmember cracks from fatigue. Replacement is straightforward - 2-3 hours to drop the trans enough for mount access. Check crossmember carefully for cracks; reinforcement or replacement adds time.

Estimated cost: $300-800

Typical onset: 120,000+ mi

Symptoms: Clutch pedal pulsation, Metallic grinding when engaging clutch, Visible crankshaft fore-aft movement, Sudden loss of oil pressure

Fix: The center main thrust bearing wears and allows crank walking. Requires full engine teardown to replace thrust washers and check main journals for scoring. If journals are damaged, crank needs grinding or replacement. Typically 22-28 hours for R&R and repair.

Estimated cost: $3,800-6,500

Typical onset: 80,000+ mi

Symptoms: Grinding into second gear especially when cold, Need to double-clutch second gear, Brass shavings in transmission fluid, Other gears shift fine

Fix: The Getrag 232 trans has weak second gear syncros. Full rebuild requires trans removal (4-5 hours), disassembly, syncro replacement, and reassembly (12-15 hours total). Many owners live with it using double-clutch technique.

Estimated cost: $1,800-3,200

Symptoms: Hard starting when hot, Stumbling at idle or part throttle, Fuel leaks from carburetor base, Won't idle without choke after sitting

Fix: Solex carburetors gum up from modern ethanol fuel. Full rebuild with new gaskets, needle/seat, accelerator pump - about 3-4 hours. Replace fuel filter, clean tank if contaminated. Many owners upgrade to Weber 32/36 for reliability.

Estimated cost: $400-900