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Service Letter SL2016-636/JWJ Splash Guarding

Based on our experience from visits on board seagoing vessels, where we have seen fuel oil (FO) connections with either incomplete or even missing splash guarding, we would like to draw your attention to installation of the required splash guarding of flanged connections in the FO
and lubricating oil (LO) system.

SL2016-621/CLN Lifetime of Fixed Cylinder Pressure Sensors

High-quality pressure measurements and a long sensor lifetime can be achieved with the proper precautionary measures and actions recommended by MAN Diesel & Turbo.

Black Spots -Cylinder liner with black lacquer and cold corrosion

Wartsila Guide for condition of relevant piston-running components
(liner, pistons and piston rings) Version 2,1 June 2014.

Stern Tube Seals Operation of AFT Seal Tank

The purpose of this bulletin is to provide operating instructions of AFT seal tank and the purpose of AFT seal tank installation.

Load Dependent Cylinder Liner (LDCL) Cooling Water System

Cylinder liner cold corrosion is counteracted by raising the temperature of the exposed parts of the cylinder liner within permissible limits by making modifications to the cylinder liner design and by making changes of the cooling water system.
The latter is done by introducing the new Load Dependent Cylinder Liner (LDCL) cooling water system.


Occasionally patches of black deposits appear on the cylinder liner wall of 2-stroke engines. The black spots may appear anywhere on the cylinder liner running surface. New cylinder liners with still honing marks (plateau honing) present seem to have a stronger tendency for black lacquer formation.


DUQ1-003E Troubleshoot of remote control system

Whenever the troubles for the remote control system have occurred the cause of trouble to be checked by suitable process not to be checked at random. This service information is made based on the trouble which have been reported in the past from many delivered ships.

SL2016-627/MIKA Tightening of Roller Guide Housing

MAN Diesel & Turbo has received reports of incidents of the roller guide housing in service. Such incidents often lead to consequential damage to the frame surface on which the housing is fixed.

SL2016-632/AAB Alpha Lubricator Service Experience

This service letter applies to MAN B&W two-stroke marine diesel engines of the MC/MC-C type.
Furthermore, the aim of the service letter is to address the service issues that have come to our attention, as well as to introduce service kits for the Alpha lubrication system.

SL2017-648/JNN New Gasket Material for Roller Guide Housing

With SL2016-627 we introduced a 10 mm washer and longer installation bolts for the roller guide housing as a preventive measure to reduce the risk of incidents caused by insuffi cient tightening of the installation bolts. A few roller guide housing incidents have been reported even after introduction of the above-mentioned washer and bolt update.

L2017-649/JNN Checking and cleaning of condensate drain trap in charge air drain system

The amount of condensate water during operation may be considerable, and must be given special attention when operating in areas with
high humidity as well as under tropical conditions. For estimation of the condensate amount in relation to the actual operation condition, we
refer to our attached descriptions 502.05 and 602.05.

DUQ1-176E Piston Ring Specifications for Modern Engines

With the increasing engine power and the recent change in the situation for engine operation, for example, popularization of low load operation, reducing cylinder oil consumption, degrading heavy fuel oil, and so on, required performance of piston ring becomes increasingly sophisticated.

DUQ1-184E Cylinder Liner Calibration

In order to estimate piston running condition and/or determine suitable overhauling interval of cylinder liner, it is very important to understand exact trends of cylinder liner wear. There is a possibility that erroneous liner wear data by an improper measurement leads to a misjudgment about cylinder liner condition.

DUQ1-185E Leaked fuel ways and telltale on IFA and related parts

When fuel leakage occurs at IFA (Intermediate Fuel Accumulator) and related parts on IFA, leaked fuel is led to sight glass or inspection cocks in order to detect and find damaged components.

SL2017-650/SRJ Guiding Overhaul Intervals

Based on the latest service experience and engine development we are pleased to issue a revised version
of the Guiding Overhaul Intervals tables. The guiding overhaul intervals apply to electronically controlled ME type engines, dual fuel ME-GI type engines, and me - chanically controlled MC type engines.

DUQ1-017E-2 Metal loss and heat crack of FOV atomizer Pocket on Cylinder Cover

Cases have been reported where cylinder cover were found like burning off and / or heat crack in the vicinity of the pocket for fuel nozzle atomizers is attributable to attack by high temperature corrosion such
as Vanadium attack (See to Fig.1).
The most probable cause of this phenomenon would be resulted from the following reasons

DUQ1-008E Cracks on Piston skirts RTA58 -68 - 76 - 84

It was ascertained that on some RTA "8" series engines in service piston skirts have been cracked at the flange clamped between a piston head and a piston rod, when they were overhauled. On this problem, the licensees in Japan have been examining and investigating earnestly in cooperation with each other as well as the licenser, Sulzer, and then we reached a conclusion that the piston skirts can be employed continuously without any problem though they get cracks.

DUQ1-006E RTA Type Engines Simple Estimation of Piston Ring Wear Amount

For measurement of a piston ring wear amount, it is an usual way to remove a piston ring and measure the ring width by using a gauge. This requires much expense and time because of the necessity of piston with drawing.
Therefore, we introduce a method in which the wear amount can be estimated indirectly by ring gap length hereinafter:

DUQ1-005E-1 RTA / RT-flex Exhaust valve air spring, low air pressure problem

An increasing of an air consumption of the exhaust valve air spring will effect the exhaust valve timing to make engine performance worse. In case the air pressure is too low, the engine will be tripped during operating or can not start.


SL2017-653/PRP MAN B&W Accumulators - All Makes

We refer to our service letter SL2006-469 concerning accumulators.
The information in this letter and in the instructions attached replaces the information given in our service letter SL06-469/JOF.
To prevent undesirable pressure peaks in the hydraulic oil system, we emphasise the importance of checking the nitrogen pressure regularly, which according to the instruction manual means every 2,000 hours or every 6 months, whichever occurs first.