Learn Turkish: Arabası herhalde kazada hasar görmüştür. - His car has probably been damaged in the accident.

The suffix -tür here is the epistemic -DIr ending, which expresses a strong guess or assumption. When you attach it to the -mIş past tense, it translates to "must have been" or "probably was". If you just used gördü, it would mean you know for an absolute fact that it was damaged.

If herhalde already means "probably", isn't adding the -tür suffix redundant?

It might feel redundant in English, but it's very natural in Turkish! Adverbs of probability like herhalde (probably) or belki (maybe) are frequently paired with the -DIr suffix on the verb. They work together to emphasize that the statement is an assumption.

Why does the sentence use the verb görmek (to see) for a car being damaged?

In Turkish, "to be damaged" is expressed with the compound verb hasar görmek (literally "to see damage"). The verb görmek is often used this way to describe experiencing a condition, similar to zarar görmek (to be harmed / to suffer a loss).

What does the -sı in arabası do here?