How to Find Your Engine Code
It takes a torch and two minutes, once you know where to look. The catch is that the location is not the same across manufacturers, or even across families from the same manufacturer.
The engine code is the single most useful piece of information you can give a supplier. It turns "I need an engine for a 2006 Accord" into a specific part, and it removes the guesswork that produces wrong-engine deliveries.
Most people do not have it, and most guides that promise to help give one location for an entire manufacturer. That is where the trouble starts, because Honda alone stamps its engines in two different places depending on the family.
Where each family is stamped
This is the part that most published guidance gets wrong. Honda in particular is often described as if every engine carries its code in the same spot, which sends people to the wrong side of a K-series engine and leaves them concluding the stamp has worn away.
| Family | Where the code is stamped | Notes |
|---|---|---|
| Honda K-series (K20, K24) | Machined pad on the driver's side of the block, near the starter | Below the head deck. Not the front face. This is the one guides get wrong. |
| Honda B-series (B18, B20) | Front face of the block, between the engine and the radiator | Flat machined pad, visible from above on most installations. |
| Honda D-series (D17) | Front face of the block, between the engine and the radiator | Same location as the B-series. |
| Honda R-series (R18) | On the block; single-cam valve cover distinguishes it from a K-series | If the car is an Si it is not an R-series regardless of year. |
| Honda J-series (J35) | On the block; suffix identifies generation and specification | V6. Check for cylinder deactivation hardware separately. |
| Toyota (2AZ-FE, 2JZ, 1JZ, 1UZ) | Stamped on the block | The family designation includes the suffix: 2AZ-FE, not "2AZ". |
| Nissan (VQ35DE, QR25DE) | Stamped on the block | Confirm DE versus HR on 3.5-litre V6 engines. They are different engines. |
| Subaru (EJ25, EJ20) | Stamped on the block | Counting camshafts separates naturally aspirated from turbocharged variants. |
What to do before you go looking
Five minutes of preparation makes the difference between reading a code and giving up on a dirty block.
- Let the engine cool completely. You will be putting your hands near the block.
- Take a torch and a phone. The stamp is often in shadow, and photographing it is easier than reading it in place.
- Take a rag and a little degreaser. Two decades of road film hides a stamp completely, and wiping the pad is usually all that is needed.
- Photograph the stamp rather than transcribing it. Zero and O, and 1 and I, are easy to confuse in a stamped alphanumeric string.
- If you cannot find it, note the year, model and trim instead. That identifies the engine on nearly every vehicle covered here.
The engine code is not the VIN
These get conflated often enough to be worth separating. The VIN identifies the vehicle and is stamped on the chassis and printed on the door jamb and registration. The engine code identifies the engine and is stamped on the block.
Both are useful and they do different jobs. The VIN tells a supplier what your car left the factory as, which is how the correct engine is identified when you cannot read the code. The engine code tells them what is physically in the car now, which matters if the vehicle has ever had an engine change.
On a modified car, or one with unknown history, the code on the block is the more reliable of the two.
Reading the suffix, not just the family
Almost every family covered on this site spans variants that differ in ways that matter. "K24" is not a part. "K24A2" is.
The suffix is the part of the code that carries the specification: the cylinder head, the intake manifold, the compression ratio and often the engine management. Two engines with the same first three characters and different suffixes can be entirely unsuitable substitutes for one another.
So when you photograph the stamp, capture the whole string. The characters after the family code are the ones that will decide what a supplier can offer you.
Common questions
How do I identify my engine code without opening the hood?
You can get most of the way there from the year, model and trim, which is how the vehicle pages on this site are organised. That identifies the engine on nearly every vehicle covered here. The stamp is what settles it definitively: particularly on an older or modified car where the original engine may have been replaced.
Is the engine code the same as the VIN?
No. The VIN identifies the vehicle and lives on the chassis and door jamb; the engine code identifies the engine and is stamped on the block. Both are useful for different reasons, and where they disagree the block stamp is the more reliable guide to what is actually in the car.
The stamp is unreadable. What now?
Clean the pad with a rag and a little degreaser first. Road film hides more stamps than wear does. If it is genuinely illegible, supply the VIN instead. That identifies what the vehicle was built with, and a supplier can work from it.
Related pages
- EnginesEvery engine family covered here, by manufacturer.
- VehiclesFind the engine your vehicle was built with, by model and trim.
- How to Verify Engine FitmentThe checks that decide whether an engine will actually work in your car.
- Engine FinderTell us the vehicle and we identify the engine before quoting it.
Find the right engine for your vehicle
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