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.
The engine serial number is stamped on an engine block pad in order to identify the place and time of manufacture. In most cases the engine serial number will also contain a 1-3 digit code that identifies the engine type. In the case of single digit codes, this engine code may conform to the code used to identify the engine in the VIN.
The engine serial number is usually found on the front or rear of the engine block to the sides of the engine. In some cases other codes or engine labels are also found in the vicinity of the engine serial code pad or on the valve covers.
INLINE 6-CYLINDER ENGINES
On inline 6-cylinder engines, the serial number is found on a pad at the front right hand side of the cylinder block, just to the rear of the distributor.
V6 AND V8 ENGINES
On the 262 V6 and all V8 engines, except the 307 Oldsmobile produced engine, the serial number is found on a pad at the front right hand side of the cylinder block, just below the cylinder head. On the 231 V6, the number can be found on a pad on the left side of the cylinder block, where it meets the transmission. On the 307 Oldsmobile produced engine, the number can be found on a tag located on the oil fill tube assembly.