Start with the manufacturer's manual
The turbocharger manufacturer sets the maintenance and overhaul intervals for each type, and the class and the vessel's planned maintenance system add their own requirements. This article gives no hours or years on purpose, because the right interval depends on the type, the fuel, the load profile and the condition of the unit. Check the intervals in the manufacturer's manual and in your planned maintenance records. What follows are signs that a unit may need attention earlier than planned, or that an overhaul due soon should not be postponed.
Changes in performance readings
Performance trends are often the first indication. Watch for charge air pressure that is lower than before at the same engine load, exhaust gas temperatures that are higher or less even than before, changes in turbocharger speed compared with your baseline, and a unit that needs washing more often or fouls again soon after cleaning. A single reading means little. A steady drift against earlier records is what deserves attention, and the air filter, the air cooler and the exhaust path should be checked before the turbocharger itself is blamed.
Vibration and noise
New or increasing vibration, a changed sound during operation or unusual noise on the air side can point to bearing wear, imbalance, deposits or damage. After the engine is stopped, a run-down that is noticeably shorter or rougher than usual, or that is accompanied by scraping sounds, may indicate bearing wear or contact between parts. Treat these as warnings and follow the manufacturers' guidance on whether the unit can keep running.
Oil leakage and smoke
Oil traces around the seals, oil in the charge air cooler or air system, oil on the turbine side or visible smoke can show that seals or bearings are no longer in good condition. These signs can also come from the oil system, from pressure conditions around the turbocharger or from the engine, so the cause needs to be established and not assumed.
Findings from inspection and oil checks
Periodic inspections and oil checks give direct evidence. Blade erosion, corrosion, cracks, rub marks, heavy deposits, excessive bearing clearance or metal particles in the oil are findings that should be assessed by a specialist against the manufacturer's limits. Keep photos and written notes of what you find, because a later comparison is much easier when the earlier condition is documented.
An overhaul that is already due
If the manufacturer's interval is reached, an overhaul should be planned even when the readings look normal. Wear inside the unit does not always show up in the operating data until it is advanced, and an unplanned stop usually costs more than a planned one. Planning the work together with a port call or a maintenance window also gives time to arrange parts.
What to prepare before you contact a workshop
- A photo of the nameplate and the make, model and serial number.
- The operating history and the date and scope of the last overhaul, if known.
- Recent readings and trends, and any alarms or events.
- Photos of anything visibly wrong, such as oil traces, deposits or damage.
- The vessel's schedule and the time available.
With this information a specialist can tell you whether an inspection, a cartridge exchange or a full overhaul is the likely route, and what still needs to be checked.
Frequently asked questions
How often should a marine turbocharger be overhauled?
Follow the intervals in the manufacturer's maintenance manual, together with the class and planned maintenance requirements that apply to your vessel. The condition and operating history of the unit can change what is needed, so we do not give a single figure.
What are the signs that a turbocharger needs an overhaul?
Typical signs include falling charge air pressure for the same load, higher exhaust temperature, new vibration or noise, oil leakage, a rougher run-down after stopping, and wear or damage found at inspection. These signs can have other causes, so an inspection is needed to confirm.
Can washing or cleaning replace an overhaul?
Washing, done as the manufacturer describes, deals with fouling only. It does not restore worn bearings or damaged blades, so if the problem continues after cleaning, the unit should be inspected.
Next step
Read about the causes of turbocharger failure, about turbocharger surging and about rotor balancing, which is part of every overhaul.
Our Workshop & Recondition service covers dismantling, inspection, reconditioning, balancing and testing, and our Field Service covers work on board. Tell us about your unit through the contact page, and see Ultimate Turbocharging for the wider turbocharger service.
This article is general information and not a substitute for the manufacturer's instructions or an inspection of your unit.