1988 BMW 528E

Typical onset: any mileage on original components

Symptoms: overheating without warning, coolant weeping from water pump, expansion tank cracking, radiator neck fracture

Fix: At 35+ years old, plastic components are brittle. Replace water pump, thermostat, upper/lower hoses, expansion tank, and radiator as a complete system. 4-6 hours labor for the full refresh.

Estimated cost: $800-1,400

Typical onset: unknown service history or 60,000+ mi since last change

Symptoms: no-start after driving, rattling from front of engine, catastrophic engine failure if belt snaps

Fix: The M20 is an interference engine. If the belt or idler bearing fails, expect bent valves and possible piston damage requiring a complete valve job or engine rebuild. Prevention: replace belt, tensioner, and idler every 50k miles. Belt job is 3-4 hours; valve job is 12-16 hours; full rebuild 20-30 hours.

Estimated cost: $400-700 (preventive) / $3,000-8,000 (repair after failure)

Typical onset: 120,000-180,000 mi

Symptoms: harsh 2-3 shift, slipping under load, delayed engagement into gear, burnt fluid smell

Fix: The ZF 4HP22 transmission develops internal clutch wear and valve body issues. Fluid/filter service every 30k miles helps, but most need a rebuild by 150k. Rebuild involves removing transmission, replacing clutches, seals, and valve body components. 10-14 hours labor for R&R and rebuild.

Estimated cost: $2,500-4,000

Typical onset: 80,000-150,000 mi

Symptoms: clunk on takeoff or deceleration, vibration at idle in gear, shifter shake

Fix: Rubber mounts deteriorate and separate. Transmission mount is accessible from below; differential mount requires subframe drop. 2-3 hours for transmission mount, 4-5 hours for both if doing differential mount simultaneously.

Estimated cost: $400-900

Typical onset: any age on original components

Symptoms: hard starting when hot, stumbling under acceleration, fuel smell in cabin, fuel pressure loss

Fix: Fuel lines, filter, accumulator, and in-tank pump all age poorly. The rubber fuel lines under the car crack and leak. Replace all flex lines, filter, accumulator, and check pump output. In-tank pump replacement requires tank drop. 3-5 hours for lines and external components; add 4 hours if replacing in-tank pump.

Estimated cost: $600-1,500

Typical onset: 100,000+ mi

Symptoms: wandering rear end, clunking over bumps, uneven tire wear, misalignment that won't hold

Fix: The semi-trailing arm bushings crack and the subframe mounts compress. This destroys rear alignment stability. Requires pressing out old bushings and installing new; subframe mounts need replacement simultaneously. 6-8 hours labor for complete rear suspension refresh.

Estimated cost: $1,200-2,000

Typical onset: 150,000+ mi

Symptoms: oil residue on rear of head, valve cover seepage, oil pan gasket weeping, small coolant loss

Fix: The M20 rarely blows head gaskets catastrophically but weeps externally over time. Valve cover gasket is 1-2 hours; oil pan gasket 3-4 hours; head gasket is 8-10 hours if needed. Most can live with minor seepage if topped off regularly.

Estimated cost: $200-400 (valve cover) / $1,500-2,200 (head gasket)