Are car repairs tax deductible if used for business and personal? I use the car about 75% for business and 25% for personal?

Yes, 75% of the repair, oil change and any expense associated with the car would be tax deductible as a business expense.  Please see Turbo Tax Article Business Use Of Vehicle to learn more about your options of Standard Mileage deductions or Actual Vehicle Expenses Deductions, along with other vehicle expenses you can claim.