E30 3-Series

1982-1994 / Sedan / Convertible / Estate / Germany

All E30 3-Series problems All workshop issues

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

Idle Control Valve (ICV) Failure

Symptoms

Rough idle, idle speed hunting (revs surging up and down between 500 and 1,500 rpm), stalling when coming to a stop, or idle sitting too high (1,200+ rpm). The engine may idle fine when cold but develop problems as it warms up.

Cause

The ICV is an electrically controlled air bypass valve that regulates idle speed. Carbon deposits from crankcase ventilation blowby clog the valve's passages. The valve's internal motor can also fail electrically.

Fix

Remove and clean the ICV with carburettor cleaner or brake cleaner.

Spray cleaner into both ports and through the valve while working the valve open and closed.

Allow to dry completely.

If cleaning doesn't resolve the issue, replace the ICV.

Cost: $0 for cleaning, $100-200 for a replacement valve.

Cost mentioned in fix

Cost: $0 for cleaning$100-200 for a

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// More E30 3-Series problems

Other known issues

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.

Critical Engine, M40 (318i, late model)

Timing Belt and Chain Issues

Rattling noise on cold start from the front of the engine (chain). Engine misfiring or loss of power (belt).

Common Engine, M40 (318i, late model)

Crankcase Ventilation (CCV) Failure

Oil consumption increases, rough idle, oil leaks, whistling noise from the engine, check engine light.

Critical Cooling System (All Models)

Expansion Tank Cracking

Coolant leak from the expansion tank, often sudden and catastrophic. The tank may crack along a seam or at the neck where the cap sits. Coolant pours out, the engine overheats within minutes.

View all 20 E30 3-Series problems