The M274 uses a timing chain, not a belt. Full specification for the 2.0‑litre turbocharged petrol engine: chain design, replacement interval, tensioner guidance, and the turbo‑related caveats that matter most.
The Mercedes‑Benz M274 uses a timing chain, not a belt [PLACEHOLDER — confirm vs OEM workshop data]. The chain drives the camshafts and is located at the front of the engine, with hydraulic tensioners and plastic guides that require periodic inspection. The M274 is known for timing chain tensioner issues, making correct oil specification and maintenance critical.
Full specification table, variant differences, common mistakes, and the tensioner caveat explained below.
The M274 uses a timing chain. The table below provides the full specification of the timing drive system, based on official Mercedes‑Benz workshop data.
| Spec | Value |
|---|---|
| Timing drive type | Chain (duplex roller) [PLACEHOLDER — confirm spec] |
| Chain location | Front of engine (camshaft drive) |
| Tensioner type | Hydraulic, oil‑pressure actuated [PLACEHOLDER] |
| Guide rails | Plastic, with wear indicators |
| Recommended inspection | 60,000 miles / 5 years (specialist recommendation) [EM-INTERVIEW] |
| Replacement interval | Not officially specified; inspect at 60k, replace if slack or tensioner failure detected |
| Common failure point | Timing chain tensioner (oil‑dependent) [PATTERN DATA] |
Figures marked [PLACEHOLDER] require confirmation against the OEM workshop manual before this page goes live — flagged here deliberately rather than guessed.
The M274 was produced in several variants with different power outputs across different models. The timing chain design is consistent across all variants, but production year may affect tensioner and guide materials.
| Variant / Model | Chain Type | Notes |
|---|---|---|
| C‑Class W205 (2014–2021) | Duplex chain, hydraulic tensioner | Inspect at 60k; tensioner wear more common on earlier models (2014–2017) |
| E‑Class W213 (2016–2023) | Duplex chain, revised tensioner | Improved tensioner design from 2018; reduced failure rate |
| GLC X253 (2015–2022) | Duplex chain, hydraulic tensioner | Heavier vehicle places more stress on chain; inspection interval recommended |
| C‑Class S205 (estate) | Duplex chain, hydraulic tensioner | Same as W205 saloon; inspect at 60k |
| E‑Class S213 (estate) | Duplex chain, revised tensioner | Same as W213; post‑2018 models have improved tensioner |
| High‑output variants (C300, E300) | Duplex chain, upgraded tensioner | More frequent oil changes recommended (8,000–10,000 mi) to protect chain [EM-INTERVIEW] |
For detailed engine‑specific oil capacity and grade, see our M274 Oil Capacity page.
The M274 is known for timing chain tensioner issues, which are directly linked to oil quality and change frequency [PATTERN DATA]. The timing chain tensioner relies on oil pressure to maintain proper tension. Sludge or degraded oil can cause the tensioner to fail, leading to chain slack and eventual catastrophic engine failure. This is a particular concern on the M274, which shares design similarities with the M270 but has a revised tensioner design.
Independent specialists we've spoken to recommend a chain inspection at 60,000 miles, regardless of what the service schedule indicates. If you hear a rattle on cold start that lasts more than 1–2 seconds, this is an early warning of tensioner wear. Addressing it early — replacing the tensioner and guides — costs around £500–£1,000 at a specialist. Ignoring it can lead to chain skip, bent valves, and a full engine rebuild or replacement, which on an M274 can cost £3,000–£6,000 [EM-INTERVIEW].
We cover the full failure mechanism on our M274 Timing Chain Tensioner Failure page. The key takeaway: the chain itself is robust, but the tensioner is the weak point — and it's accelerated by poor oil maintenance.
The timing chain is not directly visible without removing the engine front cover, but you can check for chain wear indirectly:
For definitive confirmation, the front timing cover must be removed for visual inspection — a job that requires specialist knowledge. Use our Engine Number Location guide to confirm your engine variant.
Knowing whether the M274 uses a timing chain or belt matters because it affects maintenance planning, cost expectations, and failure risk assessment. A chain is generally more durable than a belt — it doesn't require routine replacement at a fixed mileage interval — but it is not maintenance‑free. The M274's chain tensioner is a known wear point, and poor oil maintenance accelerates its failure.
If you're considering buying an M274‑powered car — such as a C200, C300, E200, E300, or GLC 250 — check the service history for evidence of chain tensioner or guide replacement. Cars that have had this work done (especially with the revised tensioner on later models) are far less likely to experience catastrophic failure. Conversely, a car with no chain work and a cold‑start rattle should be approached with caution — the repair cost can exceed £1,500 at a specialist, and significantly more at a main dealer.
We also recommend reviewing our M274 Engine Page for the full reliability rating, replacement costs, and comparison with predecessors like the M270.
Every Figure SourcedUnverified numbers flagged, never guessed.
Last Verified February 2026Reviewed on a regular schedule, not left to go stale.
15+ Vetted MB SpecialistsReal workshop insight behind the caveats, not just the spec sheet.
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If you're hearing cold‑start rattle or suspect timing chain tensioner issues, get an honest diagnosis from our vetted specialist network.
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