VIN 8th Digit Engine Codes: How to Read Yours and Match a Used Engine
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Quick Answer
The 8th character of the VIN, counting from the left, is the engine code on almost every vehicle sold in the United States. It is the only character that separates two cars of the same year, model and trim that left the factory with different engines, which is why it is the first thing we ask for. 88% of the 18,850 engine listings on this site state the VIN character in the title for that reason. Transmissions are different: only 6% of transmission listings carry a VIN character, because a transmission is identified by its option or RPO code instead.
1. Where the 8th digit sits
A US VIN is 17 characters. Count from the left and the positions mean this:
| Position | What it is | Use when ordering? |
|---|---|---|
| 1–3 | World manufacturer identifier | No |
| 4–7 | Model, body, series, restraint system | Indirectly |
| 8 | Engine | Yes — this is the one |
| 9 | Check digit | No |
| 10 | Model year | Yes |
| 11 | Assembly plant | Sometimes, on emissions variants |
| 12–17 | Serial number | No |
Find the VIN on the dash at the base of the windscreen on the driver’s side, on the driver’s door jamb sticker, and on the registration and insurance documents. Read the whole 17 and copy it; do not transcribe just the eighth character, because the model year at position 10 matters too.
2. The same digit means different things on different cars
There is no universal table, and anyone who shows you one is guessing. The character is assigned by the manufacturer, for that model, for that period. "C" on a 2012 Hyundai Sonata is a 2.4L; "C" on something else is a different engine entirely. What matters is the character for your model and year, which is why the listings here state it instead of leaving you to decode it.
A worked example from our own stock shows why the year matters as much as the character. The Hyundai 2.4L runs through these codes:
| Model | Years | 8th VIN digit |
|---|---|---|
| Sonata 2.4L | 2010–2014 | C |
| Sonata 2.4L | 2015–2019 | F |
| Sonata Hybrid 2.4L | 2011–2015 | 4 |
| Santa Fe 2.4L | 2010–2018 | B |
| Santa Fe 2.4L | 2019–2020 | D |
| Tucson 2.4L | 2010–2013 | C |
| Tucson 2.4L | 2014–2015 | G |
| Tucson 2.4L | 2018–2020 | L |
Three things come out of that table. The character changes mid-generation on the same badge. A hybrid is a different engine even at the same displacement. And two different models can share a character in the same years. "2.4 litre Sonata" is not an order; "2014 Sonata, 8th digit C, Federal emissions" is.
3. VIN digit, engine code, casting number - three different things
- The 8th VIN digit is the manufacturer’s code for the engine your vehicle was built with. It describes your car.
- The engine family or engine code is stamped or cast on the block itself. It describes the physical lump in front of you.
- The casting number identifies the block or head casting, which can be shared across several engine variants.
A fitment is confirmed when the VIN digit from your car and the identification on the actual engine agree. One without the other is an assumption. This is the whole reason we ask for the VIN before an order ships rather than after it arrives.
4. What the VIN does not tell you
Three things decide fitment that the VIN will not settle on its own:
- Emissions certification. On many 2010s vehicles the Federal, California and Canada versions of the same engine are separate part numbers. The answer is on the underhood emissions label, not in the VIN pattern.
- Mid-year production splits. Listings that read "from 4/1" or "to 3/31" exist because the part changed partway through a model year. The build date on the door jamb sticker settles those.
- Accessory and bracket differences. Two engines can be mechanically identical and still need a different bracket, sensor or connector. This is why a photograph of the actual unit is worth asking for.
5. Transmissions work differently
If you are looking for a transmission, the VIN is necessary but not sufficient. Only 6% of our 14,814 transmission listings state a VIN character, against 88% of the engine listings, because the industry identifies transmissions by option code:
- GM — the RPO code, on the sticker in the glovebox or on the door jamb
- Chrysler, Dodge, Jeep and Ram — the sales code on the build sheet
- Ford — the tag on the transmission case itself
Four things settle a transmission: model year, engine, drivetrain, and that option code. Send the VIN and the code together and the unit can be confirmed in one pass.
6. How to send it to us
Give us the full 17-character VIN and, for a transmission, the option or RPO code. We check the engine code against your vehicle before anything ships, and every unit is compression and leak-down tested before it is listed with the test sheet in the box. Every unit carries a written warranty — 3 months on 1991–2000 engines, 6 months on 2001 and newer, extendable to 3 years — parts only, labour is not included unless you buy a separate labour agreement, and freight is free anywhere in the lower 48.
- Browse used engines by vehicle — the VIN character is in the title
- Browse used transmissions
- Send us a VIN to check
Frequently asked questions
Which digit of the VIN is the engine code?
The 8th character, counting from the left. On a 17-character VIN the 8th character identifies the engine the vehicle was built with on almost every vehicle sold in the United States, and it is the one character that separates two cars of the same year, model and trim that left the factory with different engines.
What do the other VIN positions tell me?
Positions 1 to 3 are the world manufacturer identifier, 4 to 8 describe the vehicle including the engine at position 8, position 9 is a check digit, position 10 is the model year, position 11 is the assembly plant, and 12 to 17 are the serial number. For ordering an engine, position 8 and position 10 are the two that matter.
Is the 8th digit the same thing as the engine code on the block?
No, and both are useful. The 8th VIN digit is the manufacturer’s code for which engine that vehicle was built with. The number stamped or cast on the block is the engine family or casting identifier. The VIN digit tells us what your car needs; the block stamp tells us what a given used engine actually is. Matching both is how a fitment is confirmed rather than assumed.
Why does the VIN character change in the middle of a generation?
Because the engine changed while the bodyshell did not. A mid-cycle engine update, a new emissions certification or a switch of engine family all get a new character while the car keeps its name and shape. This is why ordering on the model year alone fails: a 2014 and a 2015 of the same model can take completely different engines.
What if the transmission listing does not show a VIN character?
That is normal. Only 6% of our transmission listings state a VIN character, against 88% of the engine listings, because transmissions are identified by the option or RPO code rather than the VIN. On a GM vehicle that code is on the glovebox or door-jamb sticker, on a Chrysler it is on the build sheet, and on a Ford it is on a tag on the case. Send us the VIN and that code together.