The distributor cap is a device in the ignition system that distributes electricity from the ignition coils to the spark plug wires at the right timing. It is usually made of hard plastic and a small amount of copper. Inside the distributor cap is the distributor rotor, which rotates as it receives current from the ignition coils and passes it on to the copper portion of the cap, which then passes it on to the spark plugs.
A distributor rotor also has a metal component which allows it to connect with the cables of the spark plugs of the cylinders in the engine. The rotor is mounted on the upper end of the distributor shaft, where two screws attach the rotor to a plate on top of the shaft. The rotor has built-in locators that fit snugly into the holes in the plate so it will not fall off. A centrifugal advance mechanism drives the rotor as it turns on the camshaft.
Because the distributor cap is bombarded with high voltages all the time, it must be inspected and replaced regularly. Otherwise, carbon tracking will develop in the cap and might cause misfires in the engine. Auto experts suggest replacement once in two years or every 15,000 miles of distance traveled. Owners of older vehicles should be more wary, as their caps and rotors are more prone to wear out.
The best way to check if your distributor caps and distributor rotors are working properly is at night, because you can easily see the lights that they give off from the current. You should not touch them, though, because they have as much as 20,000 volts running through them.
Distributor Cap Buyer’s Guide
- A distributor cap is used to cover distributor components and help in supplying the spark plugs with high-voltage electricity. It is often located near the center of the engine.
- Since it is found under the hood, the heat and vibrations coming from the engine can crack or break the distributor cap.
- Symptoms of a bad distributor cap include engine stalling, excessive shaking, and engine noises.
- Typically, a distributor cap can last around 30,000 miles or more. It is also often replaced during a full engine tune-up.
- A good replacement distributor cap should be made from durable materials and easy to install. It should also come with a warranty.
- You can purchase an aftermarket distributor cap for $2 to $250.
If your car won’t start, this could potentially be due to a dead battery, a bad starter motor, or a worn-out timing belt. To pinpoint the cause of the problem, there’s no better place to start than the ignition system.
Faulty ignition system components are some of the most common causes of engine failure. Once a part does not function properly, the electrical power needed to ignite the air-fuel mixture inside the combustion chamber won’t be able to reach the spark plugs. One component that can cause this is a broken distributor cap.
What is a distributor cap?
A distributor cap is a removable cover used to protect the distributor and the rotor against harmful contaminants. But aside from providing protection, it also helps in distributing high-voltage electricity from the ignition coil to the spark plugs in the correct firing order and correct timing.
Where is the distributor cap located?
You can easily find the distributor cap under your vehicle’s hood, near the center of the engine. When you pop open the hood, look for a plastic component that is connected to several thick cables. These thick cables are the spark plug wires. If you are still unsure about the location of the distributor cap, you can consult your owner’s manual.
What causes the distributor cap to fail?
Since it is constantly exposed to vibration and extreme heat, a distributor cap can wear out over time. That said, it’s normal for this component to break or crack after several years of use. Carbon deposits and corroded metal terminals can also create faulty electrical arcs that can burn the interior of the distributor cap. The same thing can happen on the distributor cap’s exterior if there is improper contact or faulty spark plug wire.
Signs of a bad distributor cap
Although symptoms of faulty ignition system components can be obvious, you have to be sure about the exact part causing the problem. If you want to confirm that you have a bad distributor cap, look for the following signs.
Vehicle won’t start
At first, it may seem like you are just finding it difficult to start your vehicle. But if the engine does not respond at all when you turn the ignition on, it is usually a sign that you need to replace your distributor cap. Without a steady flow of electricity from the distributor to the spark plugs, the combustion process won’t happen and the engine won’t run.
Strange engine noises
A faulty distributor cap or one that is clogged with dirt can also cause your engine to produce a strange sound after it starts. It may sound like a squeal or yell. Other noises like tapping, clicking, or sputtering are bad distributor cap symptoms as well.
If the distributor cap has gone bad and the engine is not running at optimal conditions, it can trigger intense vibrations in your vehicle. This is especially the case when you start your engine or shift gears. If you want this problem gone right away, better check your distributor cap for any signs of damage.
Check Engine Light
Since the engine is not performing at its best, the engine control unit or ECU will likely be alerted. This causes the check engine light on your dashboard to illuminate. Once this happens, you should inspect your distributor cap to ensure that it’s really the component causing the poor performance of your engine.
Can you still use your vehicle but notice that it stalls from time to time? This is often one of the most common signs of a bad distributor cap. The spark plugs may not be getting enough electricity to ignite the air-fuel mixture inside the combustion chambers. So once you confirm that the distributor cap is broken or damaged, make the necessary replacement ASAP so it won’t cause your engine to suddenly break down especially if you are on the road.
How long does a distributor cap last?
According to the recommendation of most car manufacturers, a full engine tune-up should be done every 30,000 miles or two years. This is usually the best time to replace ignition and fuel system components and ensure maximum engine performance and efficiency. The tune-up often includes changing the spark plugs, spark plug wires, distributor rotor, and distributor cap. The fuel filter, PCV valve, and oxygen sensor are also replaced in some vehicles.
What to look for in your distributor cap replacement?
You should opt for a distributor cap that can withstand the vibrations and heat coming from the engine. It has to be made from durable raw materials that won’t crack or break easily. It also needs to work exactly as your factory-installed distributor cap. This way, installation could be easily done.
Additionally, you should look for a distributor cap that comes with warranty. This will ensure your protection in case the part that you purchased fails after only a few weeks or months.
How much does an aftermarket distributor cap cost?
The price of an aftermarket distributor cap ranges from $2 to $250. You can buy a distributor cap in various quantities. It can be purchased per piece, in a set of two, or as part of a kit or assembly. Most aftermarket brands offer their distributor caps with a brand-dependent warranty to further protect consumers.
Finding the right fit
If you are shopping for a part or accessory at CarParts.com, make sure to use our website’s built-in vehicle selector. It allows you to select the year, make, and model of your ride before browsing the appropriate products in our inventory. By providing such information, the search results would be limited to components that specifically fit your vehicle.
To further speed up your shopping, you can choose to filter the list of products by price range, brand, location, material, and more. This can help ensure that you won’t go beyond your budget and prevent you from choosing a product that does not meet your car’s requirements and personal preferences.
Important Facts You Need to Know About Distributor Cap
Ensure a proper flow of high-volt electricity by supplying your distributor with a heavy-duty distributor cap. Purchase this product now/
There so many systems inside your car and each of them have their own specific function to fulfill. One of these systems is the ignition system. The ignition system works by providing the engine with the power to start and maintain the combustion process. And everybody knows that for your car, no combustion means no power. Such is the importance of the ignition system, and that's why you should maintain its parts. One of these ignition parts that you should look after is the distributor cap.
This ignition component consists of terminals used to transmit voltage to the engine's spark plugs. The transmitted voltage is regulated by the distributor cap rotor and is used to burn the air and fuel mixture to power the engine. Plus, this cap also provides covering for the distributor so no dirt, dust or moisture can enter it.
Once your distributor cap wears out, the performance of your ignition system will be affected. Dirt and moisture will make its way inside the distributor and its operation will be compromised. So you better take good care of this ignition component and make sure it gets the care it deserves from you. And if you need a replacement distributor cap rotor, you should get one immediately.
Distributor Cap: Just the Facts
One vital component in your vehicle's engine is the distributor cap. Designed to withstand heat and pressure, the distributor cap's primary function is to cover the distributor and its rotor. More importantly, though, the distributor cap contains the terminals through which electric current from the distributor rotor passes to the spark plugs. The distributor cap must be regularly checked to find out if the sparks are arcing from point to point within the cap. Problems with distributor cap can be verified through visual inspection. Inspect for cracks and breaks on the cap itself and on the terminal towers, as well as for gray carbon tracks. While the cap is removed, check the interior for carbon tracks and deposits and for signs of corrosion. If the damage seems too great for simple repair, your best option is to get and install a new distributor cap. CarParts.com offers the best distributor cap for your specific vehicle model.
• A distributor cap from us works more efficiently, ensuring quicker, more successful start-ups.
• Our distributor caps can endure damaging pressure and heat for longer periods, so you won't have to worry about getting a replacement.
• Our distributor caps are designed to fit most distributor models.
Buying a New Distributor Cap: Do’s and Don’ts
The distributor cap is among the key parts that make up the modern automobile's ignition system. Aside from shielding the distributor and it's rotor against dust and dirt, the distributor cap also connects the distributor to the cylinders of the engine.
Once the distributor breaks down, it's imperative that it be replaced as soon as possible. With that in mind, here are some buying tips for distributor caps that you should consider.
- DO buy a distributor cap that matches that of your car's OEM part number. OE-compliant distributor caps have their respective OEM numbers etched or labeled on the side. You can also call the dealership where you purchased your vehicle and ask for the OEM part number.
- DO buy a cap with the right number of posts. Distributor caps usually have 4, 6, or 8 distribution posts for wires at the top, with each one corresponding to the number of cylinders the car. Buying a cap that has more or fewer posts than the number of cylinders in your car will not work.
- DO buy a distributor and ignition coil as well if these also appear to be faulty. Changing the distributor cap will not automatically fix all of the problems you have with the ignition system. In some cases, the problem may also lie with the ignition coil or the distributor itself. So if both of these parts appear to be damaged or exceptionally dirty, have it cleaned or replaced as necessary aside from buying a new distributor cap.
- DON'T reuse worn or rusted clips. Distributor caps are held in place on top of the distributor using a series of metal clips. While you can certainly reuse these clips with your new distributor cap, we strongly advise against it if the clips already appear to be worn, bent, cracked, or damaged in some way. Most replacement caps come with a set of clips anyway, so you might want to consider using a new set of clips instead.
- DON'T buy a refurbished distributor cap. They may seem cheap at first, but there is no guaranteeing a refurbished cap will work properly for long. It may not even work at all.
- DON'T buy a distributor without a guarantee/warranty. You can never be sure that a distributor cap will work at first glance.
How to Change the Distributor Cap: A Step-By-Step Guide
One of the common maintenance tasks for the automobile, changing a faulty distributor cap is one skill that a car owner should know. While replacement of the distributor is complicated and best left to the experienced hands of a mechanic, the distributor cap is easy enough to remove and reinstall in your garage with a few basic tools.
Difficulty level: Moderate
- Adjustable wrench
- New distributor cap
- Spark plug wires (optional)
Step 1: Turn off the ignition and disconnect the battery cables. This will prevent against accidental electric shock and shorting out your car's electrical system.
Step 2: Pop open the hood and locate the distributor cap. It is usually located near the firewall and is easy to identify with the 4, 6, or 8 wires attached at the top and a single wire connecting to the ignition coil.
Step 3: Remove the cap with the wires still attached. Remove the metal clips holding the cap in place and gently tug on the cap until it comes off the distributor. If there is enough slack in the wires, place the cap and the wires on the side. If not, disconnect the wires and put the cap in a safe place.
Step 4: With the old cap out of the way, install the new cap into place. Make sure that you place the new cap in the same position as the old one. Once it's in place, reattach the clips on the cap.
Step 5: Attach the wires onto the new cap. Start with the wire that's closest to the #1 plug indicator on the cap then move on to the next one in a clockwise rotation. Push the wires in until you hear and feel a clicking sensation: this indicates that the wire is securely attached onto the plugs of the distributor cap.
Step 6: Reattach the battery cables and start up the engine. Check for misfires or backfiring; if these occur, check if the distributor cap and wires are installed properly. If there are still problems, you may need to replace the distributor as well.