How often should you change cap and rotor?
How often should you change cap and rotor? every 50,000 miles Replacing the distributor cap and rotor at the same time should be completed every 50,000 miles, regardless of whether or not they are damaged. If your vehicle does not put on a lot of miles every year, it's also a good idea to replace them every three years. How do you test an arm rotor? Get someone to crank the car over while with insulated pliers you hold the coil lead about 3mm away from the copper segment of the rotor arm. if you have points rotate the engine...