2026-07-22 · 5 min read
Mercedes CLS Common Problems Malaysia — C218/C257
C218 CLS350 M276 V6: valve cover leaks, oil cooler adapter seal failure, 7G-Tronic ATF degradation. C257 CLS450 M256: EQ Boost 48V battery drain, oil separator hose crack, 9G-Tronic judder. Malaysia-specific guide by generation.
CLS C218 Common Issues (M276 V6)
- Valve cover gaskets — 2 covers on V6; oil mist on engine top and burning smell
- Oil cooler adapter seal failure — oil drips down engine, contaminates transmission area
- 7G-Tronic ATF degradation — hesitation on upshift after 60,000 km without ATF change
CLS C257 Common Issues (M256/M264)
- EQ Boost 48V belt-starter-generator: belt wear and 48V battery drain — annual check
- M256 oil separator hose cracking at 50,000–80,000 km — check hose condition regularly
- 9G-Tronic judder — same issue as other 9G-Tronic models; ATF at 40,000 km