MAN D2842 Service Manual

This Repair Manual is designed to facilitate competent repair of the engines listed herein. The pictures and relevant descriptions show typical work that may not always be applicable to the engine in hand, which nevertheless does not mean that they are not correct. In such cases the repair work is to be planned and carried out in a similar way. Please note that all jobs described in this Repair Manual were carried out on an engine which was not installed. The expert knowledge necessary for handling Diesel engines was taken for granted when this publication was compiled.

Fitting flat seals / gaskets
Flat seals / gaskets are often inserted with sealing agents or adhesives to make fitting them easier or to achieve better sealing. Flat seals may slip in operation due to the “sewing-machine” effect, in particular if they are used between parts with different rates of linear expansion under heat (e.g. aluminium and cast iron), and leaks may then occur.

Example:
the cap of the front crankshaft seal. If a sealing agent or an adhesive is used here the flat seal will move inwards in the course of time as a result of the different expansion rates of the materials. Oil will be lost, for which the shaft seal may be thought to be responsible.

Flat seals / gaskets can be fitted properly only if the following points are observed:

1. Use only genuine MAN seals/gaskets.
2. The sealing faces must be undamaged and clean.
3. Do not use any sealing agent or adhesive − as an aid to fitting the seals a little grease can be used if necessary so that the seal will stick to the part to be fitted.
4. Tighten bolts evenly to the specified torque.

Faults and possible causes
We recommend
Repair work is to be considered complete only after the damage which has occurred and the possible causes have been eliminated. Ascertaining the causes of damage is frequently more difficult than eliminating the damage caused. For this reason we recommend you have the operational fault exactly described to you before removal or disassembly work is commenced. Then, track down the probable causes by asking specific questions, examining and eliminating these causes one by one with the aid of the table and your own experience. This helps to reduce repairs to those necessary and counter complaints about “premature” exchange of parts and expensive working and downtimes.

Remark:
The subsequent list is meant to be a memory aid so that no causes of damage will be overlooked in the elimination of faults. The precondition for this, however, is that you are familiar with the Repair Manual for the engine and the relevant Operator’s Manual as well as the publication “Fuels, Lubricants, Coolants for MAN Diesel Engines”.

General notes on engine overhaul
The service life of an engine is influenced by very different factors. It is therefore not possible to specify certain fixed numbers of operating hours for general overhauls. In our view, it is not necessary to open up and engine or perform a general overhaul as long as the engine has good compression values and the following operating values have not changed significantly in relation to the values measured on commissioning the engine:

1. Charging pressure
2. Exhaust temperature
3. Coolant and lubricant temperature
4. Oil pressure and oil consumption