Learn Turkish: O eski arabadan kurtuldu. - He got rid of that old car.

In English, we say we get rid "of" something. In Turkish, the verb kurtulmak (to get rid of / to escape) requires the ablative case, which means you must add the "from" ending (-dan or -den) to the object. You can think of the literal meaning here as "He escaped from that old car."

Does the word O mean "He" or "that" in this sentence?

Based on the English translation, O means "that" and modifies the car (o eski araba). The subject "He" is hidden and just implied by the verb kurtuldu. If the sentence instead meant "He got rid of the old car," a comma would usually be placed after O (O, eski arabadan kurtuldu) to clearly show it is acting as the subject "He".

If arabadan takes the -dan ending, why doesn't the adjective eski change too?

In Turkish, case endings like the ablative -dan are only attached to the noun at the very end of the phrase. Adjectives like eski (old) and pointing words like o (that) stay exactly as they are in their dictionary form.

Does kurtulmak only mean "to get rid of"?

Kurtulmak can also mean "to be saved" or "to escape." Knowing this makes it much easier to remember why this verb forces you to use the -dan (from) ending: in the Turkish mindset, you are escaping or being saved from something.