2026-08-15 · 5 min read
BMW 1 Series Oil Leak Malaysia — N20/B38 Common
F20 N20: valve cover gasket (soaks ignition coils — causes misfires), oil filter housing gasket. F40 B38: oil separator hose common, timing cover gasket. F40 B48: similar to 3 Series B48 pattern. Malaysia repair RM 300–1,000. Oil on coils causes misfire fault codes — diagnose before replacing coils.
Oil Leak Points — 1 Series
- B38: valve cover gasket, oil filter housing O-ring
- B48: oil separator hose (most common), cam cover gasket
- N55 (M135i): valley pan gasket, charge pipe oil residue
B38 Oil Separator — Common Item
The B38 3-cylinder has a crankcase ventilation system that can develop leaks at the oil separator hose connections — this is the most common oil-related issue we see on high-mileage 116i models. The failure presents as a slight burning oil smell from the intake, occasional oil mist on the engine surface, and sometimes a very slight rough idle as oil vapour enters the intake. Repair cost: RM 250–450 including parts and labour.