I have had time to read through most of the comments. "Then he looked inside" just means he looked under the hood of the car. The next line is about the engine. That is another common phrase in the US Southeast. It just means to look inside the hood of the car to look at the motor. Basically he bought the car and then after coating it in primer he took a look inside the motor compartment (or under the hood) to start juicing up the engine.