What does a car distributor do?

A car distributor is a component of the ignition system that distributes high voltage electrical power to each cylinder’s spark plug at the correct time to power the engine. It’s crucial that your distributor works smoothly, so if you notice any issues, you’ll need to get it checked as soon as possible.

Keep reading to discover how a car distributor works, how to identify if there’s a problem with it and what to do if an issue arises.

The purpose of the car distributor is to send high voltage electricity from the ignition coil to the spark plugs in the right sequence to deliver a spark which ignites the fuel / air mixture to run the engine.

The distributor consists of several parts, including the rotor arm, ignition points or electronic ignition and distributor cap that connect to the spark plug cables. Each component works in unison to keep the car engine running smoothly.

More modern cars now contain an electronic ignition system with computer-controlled sensors that determine when electricity is sent through the spark plugs. However, older vehicles up to the mid-00s usually still have a distributor.

As with most vehicle components, car distributors can experience issues over time and can be vulnerable to water damage. Here are a few tell-tale signs if you have a wet or damaged distributor:

While there are a number of reasons why your car may not start, a possibility is a faulty distributor. If your distributor cap is damaged, it may not be possible for the rotor arm to distribute the high voltage to the spark plugs.

With a faulty car distributor, the ignition timing can be impacted which can lead to the engine misfiring. If this occurs, check the distributor for any signs of wear and tear.

The check engine warning light could appear for several reasons, but the car distributor could be one, so give it a check to determine if this is the case.

If the distributor rotor arm and cap are faulty, the engine may have a misfire. The result of this is a spluttering noise from the engine coupled with poor performance.

If you think there could be a problem with your distributor, in the first instance, you’ll want to get under the car bonnet to take a look. Check the cap and rotor for any signs of cracks or arcing and if there are any loose parts or if any cables look insecure. If there are problems, you’ll need to either replace the specific parts or even the entire distributor.

Check your vehicle manual for the recommended time to get it replaced as it can vary between vehicles. Your distributor cap will also need to be replaced earlier than recommended if it becomes damaged, so it’s important to give it a check if you suspect there could be a problem.

If you discover that your distributor cap replacement is overdue, it’s essential to get it replaced as soon as possible as your car may not start if it is worn.

If you’re a confident home mechanic, it is possible to replace a car distributor yourself with the right equipment. The process can vary depending on your vehicle, so we recommend referring to your vehicle handbook beforehand, so you know what’s involved. You’ll need the following:

You’ll need to buy a replacement distributor that includes the rotor arm and distributor cap. Finding the right distributor for your vehicle is easy with Halfords. Simply enter in your vehicle registration number to bring up all the relevant car parts for your vehicle.

In terms of hand tools, you’ll need a socket set, screwdriver set and rachet spanner.

The timing specifications for your car engine can usually be found in the vehicle manual. Knowing this information is essential, so do not continue with the task if you’re unsure.

A marker pen is handy to mark the correct position of the rotor and note the order of the spark plug cables.

If you don’t feel confident in replacing your distributor, then you can always leave it to the professionals. Find your local Halfords Autocentre, book an appointment online and our experts will happily take a look.

Find 1000s of car parts you need on Halfords.com with free next working day delivery.