Camshaft adjuster magnet oil leak
Attaches to M274 at engine level · Electrical · carried by 6 variants across 4 chassis
Overview
Camshaft adjuster magnet oil leak is a common fault recorded against M274 at engine level, typically from 60–150k km. It shows up as oil around the connectors on the front of the engine, a camshaft timing fault code, and in later stages erratic running or electrical faults as oil travels along the harness. Where it's documented, the repair runs €250–€2,500 (a pair of magnets at the cheap end, a harness and control unit at the dear end, costs dated 2026-09), and it can be checked before you buy. 6 variants across 4 chassis in this database inherit it.
What happens
Symptom. Oil around the connectors on the front of the engine, a camshaft timing fault code, and in later stages erratic running or electrical faults as oil travels along the harness.
Cause. The camshaft adjuster solenoids, which Mercedes calls magnets, let oil seep past their seals and along the inside of their connectors. Left alone, the oil wicks through the wiring loom and can reach the engine control unit.
How to check it
Static checks
Unplug or inspect the connectors on the camshaft magnets at the front of the engine and look for oil inside them. Ask whether the magnets have been replaced, because catching it early is cheap.
Engine off, ideally on a lift.
Every variant that carries this
| Variant | Chassis | Body | Years | Risk | Good buy | Cost as % of good buy |
|---|---|---|---|---|---|---|
| E 200 M274 | W212 | sedan | 2013–2016 | R2 | €8,450 | 16% |
| E 200 M274 | S212 | wagon | 2013–2016 | R2 | €8,850 | 16% |
| E 250 M274 | W212 | sedan | 2013–2016 | R2 | €9,600 | 14% |
| E 250 M274 | S212 | wagon | 2013–2016 | R2 | €10,100 | 14% |
| C 200 M274 | W205 | sedan | 2014–2018 | R3 | €12,500 | 11% |
| C 200 M274 | S205 | wagon | 2014–2018 | R3 | €13,000 | 11% |
The last column is the point. The same repair is an inconvenience on one variant and a reason to scrap the car on another. A failure costing a quarter of the vehicle's value changes the purchase decision regardless of how rare it is.