سایش بلبرینگ‌های توربوشارژر

Genuine wear in the bearings supporting a turbocharger shaft that spins beyond a hundred thousand revolutions per minute on a film of engine oil. This is what an actually failed turbocharger has, and its absence is the strongest argument against replacing one.

The check is direct and quick: play in the shaft, felt by hand at the compressor wheel. Radial movement enough to let the wheel touch its housing, or noticeable end float, is the finding — and it usually arrives with company, since worn bearings let oil past the seals. Blue smoke, oil in the intake pipework and oil consumption alongside the code are the corroborating evidence; a code with none of them points elsewhere.

What causes it is nearly always oil rather than age. The bearing survives on a continuous supply of clean oil at pressure, so extended service intervals, the wrong grade, a partially blocked feed pipe, or shutting a hot engine down immediately after hard work all shorten its life dramatically — the last because the oil left standing in a glowing bearing housing cokes and restricts the feed for every start afterwards.

Fitting a new turbocharger without finding why the last one failed is how the replacement fails too. The oil feed and drain, and the reason the first one wore, belong in the repair.