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MOTRS

E24 6-Series

1976-1989 / Coupe / Germany

All E24 6-Series problems All workshop issues
Critical Engine, M30 (633CSi, 635CSi)

5. Timing Chain and Tensioner Wear

Symptoms

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.

Cause

The M30 uses a single-row timing chain with a hydraulic tensioner. Over 200,000+ km, the chain stretches and the tensioner guide rails wear. The hydraulic tensioner relies on oil pressure, when the engine sits, oil drains from the tensioner, allowing the chain to slap on startup.

Fix

Replace the timing chain, tensioner, guide rails, and sprockets.

This is a front-of-engine job requiring removal of the radiator and front covers.

Cost: $800-1,500 at a specialist.

Parts: chain (Iwis OEM, ~$80), tensioner (~$150), guide rails (~$100), sprockets (~$200).

The Iwis brand chain is the only one to use, cheap aftermarket chains stretch rapidly.

Cost mentioned in fix
Cost: $800-1,500~$80~$150~$100~$200

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// More E24 6-Series problems

Other known issues

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.
Critical Engine, M30 (633CSi, 635CSi)

7. Oil Leaks

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.
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