There's a well-worn phrase among Mercedes people: they don't build them like the M113 anymore. The data backs it up almost cruelly. The M113 V8 family is one of the most durable engines Mercedes ever made. The M273 that replaced it carries a self-destruct mechanism that can cost more than the car is worth. If you're shopping a used V8 S-Class or E-Class, this is the comparison that matters.
Quick answer: Buy the M113 (92/100, BEST) — the AMG-era V8 that runs forever. Approach the M273 (45/100, AVOID) with real caution: its idler-gear sprocket wears out (the same class-action defect as the M272), a €1,800–4,500 engine-out job. Older is very much better here.
The one that lasts
M112/M113 — 92/100 (BEST)
The M112 V6 / M113 V8 family (1997–2006) is the definition of over-engineered. Its issues are age-related housekeeping, not design flaws:
| Problem | Severity | Repair cost |
|---|---|---|
| Air suspension / Airmatic (S/ML models) | Moderate | €600–2,000 |
| Spark plugs + ignition coils | Minor | €200–500 |
| Coolant: thermostat + expansion tank | Minor | €150–350 |
The Airmatic cost is a chassis item, not the engine — the block itself is famously indestructible, which is why tuners still build on the M113 today. Keep the maintenance up and it outlives everything around it.
Found in: Mercedes C-Class, CLK, E-Class, G-Class, ML 320/350, S 430, S-Class, SL.
The one that eats itself
M273 — 45/100 (AVOID)
The M273 (2005–2012) replaced the M113 in the big cars — and inherited the era's worst Mercedes defect:
| Problem | Severity | Repair cost |
|---|---|---|
| Idler-gear sprocket wear (same class-action as M272) | Critical | €1,800–4,500 |
| Spark plugs + ignition coils (8 of each) | Minor | €400–900 |
The idler gear behind the timing cover wears its teeth, throwing metal through the engine and eventually causing failure. Fixing it means pulling the engine — the repair routinely exceeds the value of a high-mileage S 500. One critical, engine-ending fault drags an otherwise smooth V8 to the bottom of the range.
Found in: Mercedes S 500, S-Class.
Old vs new
| M112/M113 | M273 | |
|---|---|---|
| Era | 1997–2006 | 2005–2012 |
| Score | 92/100 | 45/100 |
| Verdict | BEST | AVOID |
| Defining trait | Indestructible block | Idler-gear self-destruct |
The verdict
This is the rare case where the older engine is unambiguously the better buy. The M113 is a modern classic you can run for decades; the M273 is a gamble unless you have documented proof the idler gear was addressed. If you want a used Mercedes V8, hunt down the M113 — and if you're set on an M273-era car, budget for the worst and get a specialist inspection first.
For the same "new isn't always better" story in Mercedes diesels, see OM651 vs OM654.
Scores are calculated from documented issues, repair costs, and failure patterns. Reviewed by the EngineScope editorial team. Methodology →