Engine identification can take place using various methods. The VIN, described earlier in this section, contains a code identifying the engine which was originally installed in the vehicle. In most cases, this should be sufficient for determining the engine with which your car is currently equipped. But, some older vehicles may have had the engine replaced or changed by a previous owner. If this is the case, the first step in identification is to locate an engine serial number and code which is stamped on the block or located on adhesive labels that may be present on valve covers or other engine components.