I don’t know the first thing about cars, so if mine broke, I wouldn’t know what to do. I do know, however, that ‘reparations’ is not what a car needs.
Reparations are the payments made after a war, when a defeated country pays a kind of compensation to the victorious countries. It’s similar to the word in Czech.
When we fix something on our car, or in our flat, however, we don’t use this word – we use the word ‘repairs’. So we would say, „I have to do some repairs on my car.“ We also use it as a verb, and we might also say, „I need to repair my car.“
Here is a sentence linking the two words together:
Germany had to pay a lot of reparations after the Second World War, and it took a long time to repair its relationships with the rest of Europe.