E24 6-Series

1976-1989 / Coupe / Germany

All E24 6-Series problems All workshop issues

Critical Engine, M30 (633CSi, 635CSi)

7. Oil Leaks

Symptoms

Oil residue on the engine and components. Oil smell in the cabin from oil dripping onto the exhaust manifold. Oil spots on the garage floor.

Cause

Every gasket and seal on a 40-year-old M30 will eventually leak. The most common sources: valve cover gasket (cork, hardens and shrinks), oil filter housing O-ring (hardens and cracks), oil pan gasket (cork or rubber, deteriorates), front crank seal, and rear main seal.

Fix

Full engine reseal.

Replace all gaskets and seals in one session.

The valve cover gasket is a 30-minute job.

The oil filter housing O-ring is a one-hour job.

The oil pan gasket requires lifting the engine or dropping the subframe.

The rear main seal requires gearbox removal.

Full reseal cost: $400-600 DIY, $1,000-2,000 at a workshop.

Critical: the oil filter housing O-ring leaks onto the exhaust manifold and is a fire risk, prioritise this one.

Cost mentioned in fix

cost: $400-600$1,000-2,000

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Other known issues

Critical Engine, M30 (633CSi, 635CSi)

5. Timing Chain and Tensioner Wear

Rattling noise from the front of the engine on cold start, lasting 2-10 seconds until oil pressure builds. In severe cases, the rattle persists when warm. If the chain jumps teeth, the engine timing shifts and performance drops dramatically, in worst cases, valve-to-piston contact occurs.

Common Engine, M30 (633CSi, 635CSi)

6. Bosch L-Jetronic Fuel Injection Issues (Early 633CSi)

Rough idle, hesitation on acceleration, rich or lean running, poor fuel economy. The engine may start fine cold but run poorly once warm, or vice versa.

Minor Structural and Body

1. Front Subframe Mount Corrosion

The front subframe mounting points corrode from road spray and accumulated grime. In advanced cases, the mount tears away from the body under braking or over bumps, causing a complete loss of front suspension geometry.

Minor Structural and Body

2. Rear Trailing Arm Pickup Point Corrosion

The rear trailing arm mounting points weaken from corrosion, causing the rear suspension to shift under load. Symptoms include vague rear-end handling, uneven rear tyre wear, and clunking from the rear when cornering.

Critical Structural and Body

3. Windscreen Surround Corrosion

Bubbling paint around the windscreen edges, particularly at the lower corners. By the time paint is bubbling, the underlying metal is often perforated.

Common Structural and Body

4. Door Bottom Corrosion

The lower edges of the doors develop rust bubbles. In advanced cases, the door skin perforates. Paint appears to blister from the inside out.

View all 15 E24 6-Series problems