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Engine comparison

BMW S38B35
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BMW S38B35
Verdict
RISKY · 47/100
Est. cost /3yr
€6,000-15,000 over 3 years depending on condition and required restoration work
Oil interval
7,500 km
Recalls
0
Worst issue
Head and Valve Train Damage
CRITICAL
BMW S38B35
E28 · E28
Head and Valve Train Damage
€1,500-6,000
CRITICAL
Cam Gear and Timing Chain Wear
€800-2,500
HIGH
Valve Cover and Gasket Oil Leaks
€200-600
MODERATE
Parts Availability and Escalating Ownership Costs
€500-5,000
MODERATE
General Age-Related Cooling and Rubber Component Deterioration
€300-1,200
LOW
BMW S38B35
E28 · E28
•Perform a full 6-cylinder compression and leak-down test and reject any engine below 150 psi or with more than 10% cylinder variation
•Cold-start the engine and listen for timing chain rattle in the first 10 seconds before oil pressure builds
•Inspect the cylinder head and valve cover area with a borescope for scoring, pitting or debris damage as referenced in forum teardowns
•Demand a full documented service history including evidence of regular oil changes; unserviced examples carry extreme risk
•Check all rubber coolant hoses, engine mounts and wiring loom for age-related cracking and deterioration given the 35+ year age
•Verify parts availability and get quotes for timing chain kit, cam gears and head gasket set before committing to purchase
•Confirm the car is genuinely the US-spec S38B35 (1988 E28 M5 or 1987-1988 E24 M6) and not a later E34 M5 S38B36/B38 engine swap, since displacement and part numbers differ
BMW S38B35
E28 · E28
Timing chain and tensioner
Inspect and replace if any rattle or wear evident; do not defer
100,000 km or immediately on purchase
Cam gears
Inspect for wear, cracking or slippage; replace as a preventive measure on unknown-history engines
100,000 km
All coolant hoses and thermostat
Replace all rubber coolant hoses and thermostat as a set on any newly acquired example
At purchase regardless of mileage
Valve cover gasket and oil fill cap seal
Replace gasket set to stop oil leaks before they contaminate belts or cause fire risk
At purchase or first signs of seeping
Engine mounts
Inspect and replace if cracked or collapsed; 35-year-old rubber will be degraded
At purchase
BMW S38B35
E28 · E28
No recalls on record
BMW S38B35
E28 · E28
✓Formula 1-derived engineering pedigree with proven inline-6 architecture shared with the M1 and M635CSi
✓Aluminium head with cast iron block gives robust long-term structural integrity when maintained
✓24-valve DOHC design delivers strong naturally aspirated power without forced induction complexity
✓Extremely desirable collector engine with strong enthusiast community support for technical knowledge
✓No turbo, intercooler or complex forced induction components to fail
BMW S38B35
E28 · E28
Real consumption
9.7 L/100km
Official consumption
Not available
Oil interval
7,500 km
Oil spec
10W-40 or 15W-50 high-zinc mineral or semi-synthetic (API SL or earlier spec to protect flat-tappet and cam surfaces)
Est. cost /3yr
€6,000-15,000 over 3 years depending on condition and required restoration work