The word "over-haul" generally means to repair or renovate extensively. However, there are a few antonyms that are worth considering. One could use "neglect" or "ignore" to describe a situation in which no maintenance or improvement is made. Another antonym could be "abandon," which implies a lack of interest or concern for the item in question. A third possibility is "preserve," which implies an ongoing effort to maintain and care for something in the present tense without needing to completely overhaul it. Finally, one could use "sustain" to describe a situation where ongoing maintenance is required to keep something functioning.