How to Find an Engine Number from a VIN

The short answer

Use the VIN to learn which engine the vehicle was built with. Then use one of two routes to get the actual engine number. You can read it directly from the engine block or engine label, or you can ask a franchised dealer's service department to look up the factory build record for that VIN. Free online VIN decoders, including the one run by the National Highway Traffic Safety Administration (NHTSA), can usually tell you the engine type, displacement and sometimes the cylinder count. They generally cannot give you the engine's serial number.

Two conditions change the answer. If the vehicle predates the 1981 model year, its VIN follows no standard format, so how engine information is encoded depends entirely on the manufacturer. If the engine has been replaced, the VIN still describes the original engine, not the one currently installed.

Engine code vs. engine number: know which one you need

Several different identifiers get called the engine number. Knowing which one you need saves time, because each comes from a different place.

Identifier | What it tells you | Where it is usually found; Engine code (in the VIN) | The engine type or family the vehicle was built with, such as a particular displacement and fuel system | One character or a group of characters within the VIN; Engine serial number | The unique identity of that individual engine | Stamped on the block or printed on a tag or label on the engine; also held in factory records; Partial VIN stamp | Links the engine to the vehicle it was originally installed in | Stamped on the block on many vehicles, often as the last several VIN characters; Engine family (emissions) | The emissions certification group the engine belongs to | Vehicle Emission Control Information label under the hood; Casting number | The design of the cast part, shared by many engines | Raised characters cast into the block or cylinder head

For ordering parts, the engine code is usually what a parts counter asks for. For registration questions, theft checks or confirming that an engine is original to a vehicle, you typically need the serial number or the partial VIN stamp on the block.

How to read engine information in a 17-character VIN

Vehicles built for the US market from the 1981 model year onward use a standardized 17-character VIN. The sections have defined roles, though each manufacturer decides how to fill in the descriptive portion.

Positions 1–3 (World Manufacturer Identifier): the manufacturer and, through the first character, the region where the vehicle was built. Positions 4–8 (Vehicle Descriptor Section): model, body style, restraint systems, trim code or series, and engine type, as defined by the manufacturer. Position 9: a check digit, calculated from the other characters to detect transcription errors. Position 10: the model year. Position 11: the assembly plant. Positions 12–17: the vehicle's sequential production number.

Many manufacturers selling in North America place the engine code in position 8, but this is a convention, not a universal rule. Some brands encode the engine across several characters in positions 4 through 8. Others, particularly on some imported models, do not encode the engine in a way that a general decoder can interpret. The same character can also mean different engines for different manufacturers, model years or market specifications. That is why a decoder needs the full VIN, not just the eighth character.

Step-by-step: getting the engine details from a VIN

1) Record the VIN accurately

Read the VIN from the vehicle rather than from memory or an old document. Common locations include the driver's side of the dashboard, visible through the base of the windshield, and the label on the driver's door jamb. It also appears on the title, registration and insurance card. The letters I, O and Q are not used in standard VINs, so a character that looks like O is a zero. If a decoder rejects the VIN, a mistyped character is the most likely cause, and the check digit in position 9 is what flags it.

2) Run the VIN through a decoder

Enter the full VIN into a reputable decoder. NHTSA's free decoder reports the information manufacturers submit to the agency, which often includes engine displacement, cylinder count, fuel type and model year. Commercial vehicle-history and parts-catalog tools may report a more specific engine code. Treat the result as the engine the vehicle was built with, and note any field the decoder leaves blank.

3) Ask a dealer for the build record if you need more

A franchised dealer for the vehicle's brand can usually look up the factory build data for a VIN. Depending on the manufacturer and the vehicle's age, that record may show the exact engine code, factory equipment, option codes and sometimes the engine serial number. Policies vary. Some dealers provide this freely, some charge, and some can retrieve only limited data for older vehicles. Have the VIN ready and explain what you need it for.

4) Check your paperwork

The original window sticker, a build sheet, warranty booklets and service records sometimes list the engine code or engine number. Repair invoices from engine work may also record a replacement engine's serial number. US titles and registrations typically show the VIN but not the engine number.

Finding the engine number on the engine itself

When you need the number of the engine that is actually installed, inspecting the engine is the most direct route. The location varies widely by manufacturer, engine design and model year. Treat the locations below as starting points, not guarantees.

What you will need

A bright flashlight; An inspection mirror, or a phone camera for awkward angles; A rag and a soft brush for removing grime; Optionally, chalk or a crayon to rub over a stamp and make the characters easier to read; Safe access to the underside of the vehicle, if needed: a lift, or ramps or jack stands on level ground

Before you start

Park on level ground, set the parking brake and switch the engine off. Let it cool fully, because exhaust manifolds and turbochargers stay hot long after shutdown. Keep hands and tools clear of the cooling fan and belts. On many vehicles the electric cooling fan can start by itself even with the ignition off. Never work under a vehicle supported only by a jack. If reaching the stamp would require removing components, stop and leave that to a qualified technician.

Where to look

A flat machined pad on the engine block, often near where the block meets the transmission or near the front of the engine; The area where the block meets the cylinder head, on either side of the engine; A sticker, plate or tag on the timing cover, valve cover or intake area; The owner's manual or a service manual for the vehicle, which may describe the location

Clean the area gently. Avoid wire brushes, abrasives or harsh solvents on the stamp itself, because damaging the characters can make the number hard to verify later.

Telling the right number from look-alikes

Engine blocks carry several markings, and only some identify the individual engine. Raised characters formed in the metal are almost always casting numbers. They identify the part design and appear on every engine made from the same mold. Stamped serial numbers and partial VIN stamps are punched into the surface and look indented, often on a smooth machined pad. A part number on a sticker identifies a component, not the engine as a whole. The emissions label under the hood shows the engine family and displacement, which helps confirm engine type but is not a serial number.

US anti-theft parts-marking rules require the engine and transmission on certain passenger car lines to be marked with the VIN. On many other vehicles, manufacturers stamp a full or partial VIN on the block as a matter of practice. If you find a sequence that matches the last several characters of your VIN, you have found a derivative VIN stamp. That is strong evidence the engine is original to the vehicle.

How to confirm you have the right result

The engine type from the VIN decoder matches the displacement and engine family shown on the emissions label. Any partial VIN stamp on the block matches the corresponding characters of the vehicle's VIN. The number you recorded is a stamped or printed identifier, not a raised casting number. If you obtained a dealer build record, its engine code agrees with what you found on the vehicle.

If these checks disagree, the engine may have been replaced, or the decoder may not support that manufacturer's engine coding. If the block stamp looks altered, ground off or restamped, a dealer, a qualified technician or the motor vehicle agency in your state can advise on next steps. Altered identification numbers can complicate registration and ownership.

When the VIN cannot help

For vehicles built before the 1981 model year, VIN formats were set by each manufacturer. Some older VINs include an engine code, and some do not. Model-specific references or an enthusiast club for that make are often the best way to interpret them. For a vehicle with a replacement engine, the VIN describes only what left the factory. The engine itself, or records from the shop that installed it, is the only reliable source for the current engine's number.