The aim of this brochure is to provide the interested reader with an overview of the different types of damages that can be encountered in the innermost part of an internal combustion engine, as well as to provide a useful tool for specialists which will help to diagnose faults and determine their causes. The process of assessing engine damage is similar to a medical assessment in that it requires an all-encompassing approach to identify the cause(s) of a problem, which may not always be clear and obvious. It is not at all a rare occurrence for repairs to be carried out and then for the same damage to occur again and the same components to fail again because, although the damaged parts were replaced, nothing was done to eliminate the cause of the problem. For this reason a certain amount of “detective work” is always needed to track down the fault. In many cases the engineer is presented with just a faulty component, with no information about how long the component was in service before it failed, or what the extent of the damage is. Naturally this makes it difficult to retrace how the fault happened, and the resulting diagnosis invariably offers a general, non damage-specific conclusion. All of the types of damages covered in this new, fully revised edition have been put together with the utmost care and brought right up to date. It should provide you with a comprehensive source of information which will assist you in either your work or your studies. Recognising damage is not always a straightforward task. In many cases the damage can be hard to make out in the photographs, or it may not be immediately obvious that any damage is present. This is why in addition to the photographs showing the damage you will also see damage pictograms like the one opposite. These will help you to recognise and identify the damage on the photographs more easily. These pictograms do not show the damage on a 1:1 scale. The pictograms are merely intended to serve as examples, in some cases with useful additional information. The quick diagnosis pages also enable any damage to be located and assigned quickly. Here you will also find the abovementioned damage pictograms which can be used as the basis for assigning faults to their causes, or for making at least a preliminary decision about what type of damage might be present. In some cases there are several different pictograms for the same damage. If for example damage has occurred and left behind characteristic traces on the piston and on the running surface of the liner, then there may be two pictograms for this damage with both of the relevant components and their characteristic damage patterns. A glossary has been included as an appendix with this brochure. This contains the key specialist terms used in the brochure, together with appropriate explanations.