Car distributor cap

What exactly does a distributor cap do?

A distributor's job is just that: it distributes high ignition voltage to the right cylinders at the right time.

A malfunctioning cap and rotor will send voltage to the wrong place, or no place at all. Distributor caps and rotors vary in design and complexity. Older vehicles have simple cap and rotor arrangements. Ignition systems on modern vehicles can be more complex.

Advanced or not, all moving parts eventually wear out. Distributor caps and rotors are no exception. Heat, vibration, and extreme voltage all add up to a tough life for your cap. Cracking and carbon deposits on a cap can rob engine efficiency.

Advance Auto has the quality auto parts – including distributor caps and rotors – you need to keep your car performing at its best.

Why should you inspect and replace your distributor cap?

Your engine compartment is a harsh environment. Your cap has to stand up to extreme temperatures and thousands of volts of power. The plastic in the cap simply breaks down over time and the internal plug wire contacts deteriorate from spark arcing. Hard starting, engine missing, stalling, backfiring and pinging are all signs that your car distributor cap may have called it quits.

Replace that tired old cap and rotor using a quality parts kit from Advance Auto Parts.

What you will need to replace your car distributor cap:

• Distributor cap
• New rotor
Socket set


Exhaust header do-it-yourself difficulty level:

Estimated time required - 1 Hour

How to replace distributor caps: do it yourself & save!

Ignition systems and distributor caps vary by vehicle. Please refer to your repair manual. Disconnect the negative battery cable before starting.

  1. The first step is locating the cap. This muscle car’s distributor was tucked away at the back of the engine.
  2. Loosen the old cap. This GM cap had two J-hooks. To loosen, push down and rotate 90 degrees. Other styles of caps use snap clips or machine screws for retainers.
  3. Lift the cap straight up to clear the rotor. You may have to disconnect the coil wire if it isn’t long enough.
  4. Position the old and new caps next to each other. Line up the two caps to match. Transfer spark plug wires one-by-one onto the new cap. Lift the old rotor off and install the new one making sure it is aligned as the old one was.
  5. After the wires have been installed in the new cap, place the cap on the distributor and rotate until the alignment tab allows the cap to drop in place.


Refasten the cap back onto the distributor. Double-check connections of all wires. Reconnect negative battery cable.

For high quality auto parts on all of your vehicle maintenance, trust Advance Auto Parts!