The M273 uses a timing chain, not a belt. Full specification for the 5.5‑litre V8 petrol engine: chain design, replacement interval, tensioner guidance, and the timing chain caveats that matter most.
The Mercedes‑Benz M273 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.
Full specification table, variant differences, common mistakes, and the timing chain caveat explained below.
The M273 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 and chain stretch [PATTERN DATA] |
Figures marked [PLACEHOLDER] require confirmation against the OEM workshop manual before this page goes live — flagged here deliberately rather than guessed.
The M273 was produced in several variants with different power outputs. The timing chain design is consistent across all variants, but production year may affect tensioner design.
| Variant / Model | Chain Type | Notes |
|---|---|---|
| C‑Class W204 (2007–2014) | Duplex chain, hydraulic tensioner | Inspect at 60k; tensioner wear more common on earlier models |
| E‑Class W211 (2005–2009) | Duplex chain, hydraulic tensioner | Early production (2005–2007) may have higher chain stretch risk |
| E‑Class W212 (2009–2016) | Duplex chain, revised tensioner | Improved tensioner design; reduced failure rate |
| CLS C219 (2004–2010) | Duplex chain, hydraulic tensioner | Similar risk to W211; chain stretch more common on higher-mileage units |
| S‑Class W221 (2005–2013) | Duplex chain, hydraulic tensioner | Heavy vehicle places more stress on chain; inspection interval recommended |
| High‑mileage variants (>100k mi) | Duplex chain, often worn guides | Chain stretch and guide wear become more common; oil change history critical |
For detailed engine‑specific oil capacity and grade, see our M273 Oil Capacity page.
The M273 is known for timing chain stretch issues, which are directly linked to oil quality and change frequency [EM-INTERVIEW]. The timing chain tensioner relies on clean, high‑quality oil 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 M273, which shares design similarities with the M272 V6 that has well‑documented balance shaft issues.
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 or chain wear. Addressing it early — replacing the tensioner, guides, and possibly the chain — costs around £1,000–£2,000 at a specialist. Ignoring it can lead to chain skip, bent valves, and a full engine rebuild or replacement, which on an M273 can cost £5,000–£8,000 [EM-INTERVIEW].
We cover the full failure mechanism on our M272 Balance Shaft Chain Failure page (similar principles apply to the M273). The key takeaway: the chain itself is robust, but the tensioner and guides are the weak points — and they're 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 M273 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 M273's chain tensioner and guides are known wear points, and poor oil maintenance accelerates their failure.
If you're considering buying an M273‑powered car — such as a C350, E350, CLS350, or S350 — check the service history for evidence of chain tensioner or guide replacement. Cars that have had this work done 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 £2,000 at a specialist, and significantly more at a main dealer.
We also recommend reviewing our M273 Engine Page for the full reliability rating, replacement costs, and comparison with successors like the M276.
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 issues, get an honest diagnosis from our vetted specialist network.
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