Q: Will my car turn on normally again once I fix the crankshaft position sensor?

A faulty crankshaft position sensor could cause hard starting but to determine if the sensor itself is faulty it has to actually be tested. Often, there will be a Diagnostic Trouble Code (DTC), that is generated by the car’s computer, and that turns on the Check Engine Light on the dashboard if the sensor has failed or is "failing." If your problem was actually diagnosed as a bad sensor, the paperwork that the Mechanic gave you should identify the Diagnostic Trouble Code so that you can understand what is going on with your car.

If YourMechanic performed the Check Engine Light Diagnostic, for instance, we would tell you the code and explain what it means in terms of any required repair. At any rate, to answer the heart of your question, if the mechanic checked for DTCs, found a code that "implicated" the crankshaft position sensor, and no other codes were reported, AND he properly tested the sensor and ruled out all other possible causes of hard starting then yes that repair will resolve your issue.

But that is a lot of "ifs" and that’s why it’s often good to either make sure the mechanic justifies to you what he is doing or seek a second opinion. As far as the oil level is concerned, if the oil level in the engine falls below the "lowest" mark (the "add oil" mark) on the dipstick the engine can get damaged. Indeed, the level of engine oil needs to be checked at least weekly and more often if, say, you are driving as much as 1,000 miles a week.