I rented a car and it is a 2016 Kia Optima, however, I cannot tell what kind it is. The emblems on the car just say Kia Optima with no further info. The manual and other documents are generic and do not say what kind of Optima it is. The tag inside of the door is covered up by a sticker. The possibilities are:

  • 1.6 L G4FJ Turbocharged Inline-4
  • 2.4 L Theta II I4
  • 2.0 L Theta Turbocharged I4

How can I figure out which kind it is?

2 Answers 2


Locate the VIN. This will most likely be on a metal strip on the dashboard near where it meets the windshield.

Type that VIN into a decoder like this one https://www.dmv.org/vehicle-history/vin-decoder.php

Use a decoder relevant to your country of residence (where the vehicle was registered) or to the country of origin (where the vehicle was produced.)

The result should be several pieces of information about the vehicle including engine size.

Alternatively, some engines have identifying marks printed on or near them in the engine compartment.

  • I did that and determined that the engine code is GT4L3 which of the three possibilities it is. The decoders do not tell the common name of the engine, they just give you the code. Jan 2, 2018 at 22:04
  • That doesn't match with any Optima engine codes I know.. the codes for the 2.0l Theta Engine are G4KA, G4KD, G4KF, G4KH, and G4KC, G4KE, G4KG, G4KJ for the 2.4l. The 1.6l is G4FJ in the Optima Jan 3, 2018 at 10:38
  • An optima listed on edmunds with the "GT4L3" identifier has the following engine: Engine: 2.4L DOHC I4 GDI per edmunds.com/kia/optima/2017/vin/5XXGT4L3XHG139808
    – Sam Basso
    Jan 3, 2018 at 13:45

If you have absolutely no clue, an easy way to tell which Optima you have is by the under hood emissions sticker. It should be locate very prominently and easily seen when you pop the hood. It should look something like this:

enter image description here

(NOTE: This is a generic sticker, but your under hood should be something similar.)

On the sticker, it shows just to the left of the red circle, the engine family and displacement. If you only have the three options as you're showing, easy deduction can be your friend.

  • See my comments to the previous answer. I got the engine code, but it does not tell me which engine engine it is. Jan 2, 2018 at 22:04

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