Mercedes-Benz GL-Class: M272/M273 Balance Shaft Sprocket Premature Wear

The M272 V6 and M273 V8 engines used a composite plastic balance shaft idler gear sprocket that wears prematurely, causing timing chain slack and camshaft timing errors on the right bank. The GL X164, sharing its platform and engines with the W164, is equally affected. A class action settlement was reached in 2011. Engines with M272 serial numbers below 30468993 are the most commonly documented, though failures outside this range are reported.

• Cold-start timing chain rattle lasting more than 2–3 seconds
• Check engine light with P0016 or P0017 cam correlation codes
• Rough idle or misfire
• Metallic swarf present in engine oil sample

1. 1

   Check engine serial number against the published Mercedes threshold.

2. 2

   Scan for P0016 and P0017 stored codes.

3. 3

   Listen for cold-start chain rattle at startup before the engine has warmed.

4. 4

   Inspect engine oil for metallic contamination.

5. 5

   Request documented proof of balance shaft sprocket and timing chain replacement as a set.

Parts involved: Timing chain.

$6,500 to $13,000 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the balance shaft sprocket and timing chain been replaced with a workshop invoice as evidence?”
• “What is the engine serial number?”
• “Are there any stored check engine codes related to camshaft timing?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.