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Service Letters

This is a collection of service letters published by MAN Energy Solutions, Copenhagen/Holeby, Denmark, covering both MAN B&W two-stroke and MAN four-stroke combustion engines.

Our service letters provide information on new engine developments and trends, service experience, important aspects of engine management and maintenance, and emissions requirements compliance and development, etc. 

Note that some service letters have documents attached (e.g. work cards, instructions, guidelines, specifications, etc.) that may subsequently have been updated after the release of the service letter. It is therefore recommended to check for the latest edition of such attachments.

Table of content

  • Service Letters, Two-stroke – Table of Content
    pdf, 298 KB
  • Service Letters, Four-stroke - Table of content
    pdf, 853 KB
  • Service Bulletin, Four-stroke Pielstick (available via mail request to – Table of content
    pdf, 532 KB


  • SL2023-745
    pdf, 432 KB
  • SL2023-744
    pdf, 864 KB
    Guiding overhaul intervals
  • SL2023-743
    pdf, 3710 KB
    Updated procedure due to potential crack in piston crown
  • SL2023-742
    pdf, 470 KB
    Pre-inspection of turbocharger hot-parts
  • SL2023-741
    pdf, 580 KB
    Biofuel operation
  • SL2023-740
    pdf, 674 KB
  • SL2023-739 NSL
    pdf, 598 KB
    PMI sensors - Two-stroke engines
  • SL2023-738
    pdf, 1016 KB
    Sampling of scavenge drain oil: Adjust feed rate factor in service, and monitor piston ring and cylinder liner wear
  • SL2023-737
    pdf, 1592 KB
    CyIinder lubrication update for operation on ULSFO, VLSFO, biofuel, LNG, LEG, LPG, methanol, and HSFO
  • SL2023-736
    pdf, 590 KB
    MAN NOx sensors – for SCR and EGR
  • SL2023-735
    pdf, 677 KB
    Reconditioning of exhaust valve spindles
  • SL2023-734
    pdf, 811 KB
    Local monitoring control and safety, LMCS base module 2 replacement.
  • SL2023-733
    pdf, 578 KB
    Starting air valve - Failure to close
  • SL2023-732
    pdf, 1195 KB
    Fees for technical assistance and advisory work.
  • SL2022-731
    pdf, 884 KB
    Correct installation of lubricating oil supply valve for the Alpha Lubricator. Non-flow cylinder oil alarm
  • SL2022-730
    pdf, 2614 KB
    Prevention of crankcase explosions. The latest safety components standard
  • SL2022-729
    pdf, 847 KB
    Preventive grinding of exhaust valve seats
  • SL2022-728
    pdf, 508 KB
    Cylinder and system oils MAN B&W low-speed two-stroke engines
  • SL2022-727
    pdf, 772 KB
    Regular dp-RTV and RTV position check of SCR installations
  • SL2022-726
    pdf, 3213 KB
    Service experience with 2020-compliant fuels
  • SL2022-725
    pdf, 681 KB
    Updated evaluation guidelines - piston ring coating and deposit build-up on piston ring lands
  • SL2022-724
    pdf, 873 KB
    Inlet and exhaust valve issues when operating on low-sulphur fuels
  • SL2022-723
    pdf, 487 KB
    EEXI Compliance
  • SL2022-722
    pdf, 539 KB
    Running without gas injection for prolonged periods
  • SL2022-721
    pdf, 850 KB
    Excessive wear on the locking keys of crankshaft thrust bearing.
  • SL2022-720
    pdf, 1263 KB
    Fees for technical assistance and advisory work
  • SL2021-719
    pdf, 687 KB
    Cleaning of fuel injection nozzles
  • SL2021-718
    pdf, 882 KB
    Overspeed incident with disintegrated flywheel ̶ Updated information
  • SL2021-717
    pdf, 690 KB
    Safety during emergency repair Safety precautions
  • SL2021-716
    pdf, 538 KB
    Reaming of valve guide after replacement

All data provided on this site is for information purposes only, explicitly non-binding and subject to changes without further notice.

Unless otherwise stated, the copyright and any other rights in the contents of the Service Letters available through our website, including any images and text, are owned by MAN Energy Solutions.

For the avoidance of doubt, you must not adapt, edit, change, transform, publish, republish, distribute, redistribute or show in public the Service Letters (in any form or media) without the prior written consent of MAN Energy Solutions.

Permission is granted to:

1) download, display or print material for personal use or use within an individual organisation and for a non- commercial purpose;

2) create links to these pages;

3) reproduce short extracts provided the source is stated. 


Requests for further authorisation regarding proposed usage of the information provided should be addressed to: 

MAN Energy Solutions
Teglholmsgade 41
2450 Copenhagen SV
or by email to

Requests of the S.E.M.T. Pielstick Service Bulletin should be addressed to: 


MAN Energy Solutions France
Attention: Technical Assistance MAN PrimeServ
Avenue de Chatonay , Porte 7
BP 427
44615 Saint-Nazaire Cedex
or by email to