No, do not use it. Leave it for chicken grease on the pan. It is not safe for your car to use dish soap. However, many people use it and do not complain. But it is not ideal for a car wash as it may roughen the surface. It will clean the car, of course, but the after-effects will be harmful. The reason why you should not use it is that it may not be as effective. And because it is not made for cars, it may clog and gum up the components. So, if you continue to use it, it will harm your paint in the long run. I hope you get your answer to is dishwashing liquid is good for washing cars.