E30 3-Series

1982-1994 / Sedan / Convertible / Estate / Germany

All E30 3-Series problems All workshop issues

Critical Rust

Battery Tray Corrosion

Symptoms

The battery tray (in the engine bay, passenger side) corrodes through. Acid from the battery eats through the metal tray and then attacks the chassis rail underneath.

Cause

Battery acid vapour and minor spills corrode the mild steel tray. Old batteries that vent acid during charging accelerate the process.

Fix

Remove the battery and inspect the tray.

Surface corrosion: wire brush, treat with rust converter, prime and paint.

Perforation: weld in a repair patch or fabricate a new tray.

Inspect the chassis rail beneath, if it's corroded, professional repair is required.

Cost: $100-300 for tray repair, $500-1,500 if the chassis rail is affected.

Cost mentioned in fix

Cost: $100-300 for tray$500-1,500

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// More E30 3-Series problems

Other known issues

Minor Rust

Rear Shock Tower Corrosion

The sheet metal around the rear shock absorber mounting points corrodes and weakens. In severe cases, the shock pushes through the floor of the boot. The car may sit unevenly, or you may hear clunking from the rear.

Common Rust

Front Subframe Mount Corrosion

Cracking, crumbling, or perforation of the unibody metal where the front subframe bolts to the chassis. May be visible as rust around the subframe bolt holes when viewed from underneath.

Common Rust

Jacking Point Corrosion

The factory jacking points crumble when you try to jack the car up. The jack punches through the corroded metal.

Minor Engine, M20 (320i, 323i, 325i, 325e)

Timing Belt Failure

The engine stops instantly while driving. If the belt snaps at speed, the valves collide with the pistons, destroying the cylinder head and potentially the pistons as well. The engine is scrap without a full rebuild.

Critical Engine, M20 (320i, 323i, 325i, 325e)

Head Gasket Failure

Coolant loss without visible external leak. White smoke from the exhaust (coolant burning in the combustion chamber). Overheating. Milky emulsion under the oil filler cap. Coolant in the oil (oil level rises, oil appears grey or milky on the dipstick). Bubbles in the expansion tank with the engine running.

Critical Engine, M20 (320i, 323i, 325i, 325e)

Oil Leaks, Everywhere

Oil weeping from the valve cover gasket, oil filter housing gasket, oil pan gasket, rear main seal, and front crank seal. A high-mileage M20 will have oil residue on virtually every surface.

View all 20 E30 3-Series problems