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MOTRS

E28 / E34 5-Series

1981-1996 / Sedan / Germany

All E28 / E34 5-Series problems All workshop issues
Minor Cooling System (Both Generations)

5. Expansion Tank Failure

Symptoms

The expansion tank cracks without warning, dumping coolant. The engine overheats rapidly, often within 5 minutes of the leak starting. The crack typically occurs on the side of the tank or at the plastic seam. On the E34, the tank is mounted on the left inner wing; on the E28, it's on the right.

Cause

The expansion tank is made of plastic that becomes brittle with age and heat cycling. Every thermal cycle, heating when the engine runs, cooling when it's off, weakens the plastic. After 15-20 years, the tank is a ticking time bomb.

Fix

Replace the expansion tank proactively every 5-7 years.

E28 expansion tank: $40-70.

E34 expansion tank: $50-80.

This is a 15-minute job.

Replace the cap at the same time, the pressure relief valve in the cap is critical for system pressure regulation.

Always carry a spare expansion tank in the boot.

Cost mentioned in fix
$40-70$50-80

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Other known issues

Minor Cooling System (Both Generations)

6. Water Pump Impeller Failure

The engine overheats despite the cooling system appearing intact, no leaks, hoses firm, fan running. The temperature gauge climbs steadily in traffic or at low speed.
Critical Engine, M30 (E28 535i, E34 535i)

1. Timing Chain and Tensioner Wear

Rattling from the front of the engine on cold startup, lasting several seconds until oil pressure builds. The rattle may also appear briefly when restarting a warm engine. In severe cases, a constant rattle or chain slap noise.
Critical Engine, M30 (E28 535i, E34 535i)

2. Oil Leaks (M30)

Oil weeping from the valve cover gasket, oil filter housing gasket, oil pan gasket, rear main seal, and front crank seal. Oil residue on the underside of the engine and on the exhaust manifold.
Common Engine, M50/M52 (E34 520i, 525i, 530i)

3. VANOS Seal Failure

Rattling from the front of the engine on startup, loss of power and torque below 3,000 rpm, rough idle, and in some cases a check engine light. The engine may feel flat and unresponsive at low RPM but pull normally above 4,000 rpm.
Minor Engine, M50/M52 (E34 520i, 525i, 530i)

4. M60 V8 Nikasil Bore Wear (E34 530i, 540i)

Progressively worsening cold-start difficulty, rough idle when cold that smooths out as the engine warms, increasing oil consumption (more than 1L per 1,000 km), and eventually misfiring and low compression.
Common Electrical

7. E28 Instrument Cluster Pixel Failure

The LCD segments in the instrument cluster fade, become incomplete, or disappear entirely. The odometer, trip meter, clock, and service indicator displays are all affected. In severe cases, the entire LCD is unreadable.
View all 14 E28 / E34 5-Series problems