You might be looking at your car and wondering, how many spark plugs in a 4 cylinder engine? You’re not alone. I had the same question when my car started making weird noises. The simple answer is: a 4-cylinder engine usually has 4 spark plugs, one for each cylinder. But some engines have more. Sounds confusing, right? In this article, you’ll learn everything in very easy words. I’ll explain it just like you’re sitting next to me.
What Are Spark Plugs and What Do They Really Do?
Spark plugs are very small parts inside your car’s engine, but they do a very big job. They make a tiny spark, and that spark helps your engine run. Without spark plugs, your car will not start. It’s like trying to cook without fire. Nothing will happen.
Each cylinder in your engine needs one spark plug to work. The spark plug gives fire to the air and fuel mix inside the cylinder. This makes the explosion that moves your car. It’s a very fast and repeating action. The spark plug fires many times every second when the engine is running.
But not all engines are the same. Some engines have one spark plug for each cylinder, and some have two spark plugs in each cylinder. This is where people get confused.
In most normal 4-cylinder engines, there are 4 spark plugs — one for each cylinder. This is the most common setup. If you have a simple, regular car with a 4-cylinder engine, you probably have 4 spark plugs.
But some special engines like the ones from Alfa Romeo, Chrysler, or certain Dodge models might have 8 spark plugs for a 4-cylinder engine. This is because they use twin spark technology. That means they put two spark plugs in one cylinder to make the explosion better and smoother.
You don’t need to worry unless your car manual says so. Always check your owner’s manual or ask a mechanic if you are unsure.
Let me tell you a real story. A friend of mine had a Dodge Neon with a 4-cylinder engine. One day, it started to shake and lose power. He thought one spark plug was bad. When he opened the hood, he found 8 spark plugs! He was surprised. Later he learned it was normal for his car because it used two spark plugs per cylinder.
So remember, a 4-cylinder engine usually has 4 spark plugs, but some may have 8 if they use twin spark. Knowing this can save you money and help you avoid confusion when changing spark plugs.
- Spark plugs create small sparks to start your engine.
- Each cylinder usually needs one spark plug.
- Most 4-cylinder engines have 4 spark plugs.
- Some special engines have 8 spark plugs.
- Always check your car manual or ask a mechanic.
How to Count Spark Plugs in a 4 Cylinder Engine
It’s easy to say there are 4 spark plugs in a 4-cylinder engine, but how do you actually check? Maybe you want to see it for yourself. Don’t worry — I’ll walk you through it step by step in a very simple way. You don’t need to be a mechanic.
First, make sure your car engine is off and cool. Never open the hood when the engine is hot. It can burn your hand. Once the engine is cool, open the hood of your car and look at the top of the engine.
Most spark plugs are found on top or on the side of the engine. Look for thick black wires or coils that go down into the engine. These wires or coils are usually connected to the spark plugs. In most 4-cylinder engines, you will see 4 of these coils or wires, one for each spark plug.
Now count them. If you see 4 wires, you likely have 4 spark plugs. If you see 8 wires or 8 coil packs, then your engine has 8 spark plugs. Sometimes, the second spark plug is placed in a different location, so you may need to look carefully.
Some engines hide the spark plugs under plastic covers. You might need a screwdriver to remove the plastic engine cover. Once removed, you can clearly see how many coils or wires are plugged into the engine. Each wire or coil goes to a spark plug.
Another way is to use your owner’s manual. It will tell you how many spark plugs are in your car. You can also search online using your car’s make, model, and year. Type it like this in Google: ‘how many spark plugs in 2015 Honda Civic 4 cylinder’.
Let’s say you still can’t figure it out. You can always take your car to a local mechanic or even an auto parts store. Most of them will check it for free. They can even tell you the exact type of spark plugs you need.
Also, be careful when buying spark plugs online. If you buy only 4 but your engine has 8, you’ll end up needing more. Some people only replace half by mistake and that can damage your engine.
- Let your engine cool before opening the hood.
- Look for wires or coils on top of the engine.
- Count the wires to know how many spark plugs.
- Use your owner’s manual or search online for your car model.
- Ask a mechanic if you’re not sure.
Why Some 4 Cylinder Engines Have 8 Spark Plugs
This is where things get interesting. You might wonder, why would a 4-cylinder engine need 8 spark plugs? It seems strange, right? But there’s actually a good reason for it.
Some engines use what’s called a twin spark system. That means each cylinder gets two spark plugs instead of one. This helps the engine burn fuel more evenly and quickly. When fuel burns better, the engine makes more power and produces less smoke. It also helps save fuel and keeps the engine cleaner.
Cars like some Alfa Romeo, Mitsubishi, Dodge, and Chrysler models use this system. Twin spark is often used in engines that want better performance without making the engine bigger.
Each of the two spark plugs fires at the same time or at a very small delay. This makes the explosion inside the cylinder stronger and more even. It helps the engine run smoother, especially at high speeds.
There’s also another reason: emissions control. Some engines use two spark plugs per cylinder to make sure all the fuel burns. This helps reduce harmful gases from going into the air. It’s good for the environment and also helps the car pass emissions tests.
However, there’s a downside too. If you have 8 spark plugs, it means more work and more cost when it’s time to replace them. You need to buy 8 spark plugs instead of 4. And the labor to change them can be double. But the good part is, twin spark engines don’t always need new plugs as often because they burn fuel better.
One important thing to remember is: never guess how many spark plugs your engine has. Always check your manual or look under the hood. Even if your engine is 4-cylinder, it doesn’t mean it only has 4 spark plugs.
- Some 4-cylinder engines use 2 spark plugs per cylinder.
- Twin spark systems improve fuel burn and engine power.
- They help reduce emissions and make engines smoother.
- Cars like Dodge, Chrysler, and Alfa Romeo may have 8 plugs.
- Always check to avoid surprise costs when replacing plugs.
When to Change Spark Plugs in a 4 Cylinder
Even if you know how many spark plugs your 4-cylinder has, the next big question is when to change them. This is very important for your car’s health.
Spark plugs don’t last forever. They wear out after many miles. Most spark plugs last between 30,000 to 100,000 miles, depending on the type. Cheap copper plugs last less. Platinum and iridium spark plugs last longer.
If you don’t change your spark plugs on time, your car can have many problems. It can misfire, lose power, use more fuel, and even damage the engine.
Here are some signs that your spark plugs need changing:
- Your car takes long to start
- You hear weird sounds or feel shaking
- Your fuel mileage is getting worse
- The engine light comes on
- You feel a loss of power when you drive
The best way to know is to check your owner’s manual. It will tell you when to replace spark plugs. If you drive a lot, you may need to change them sooner. Also, always replace all spark plugs at the same time. If your 4-cylinder engine has 4 spark plugs, replace all 4. If it has 8, replace all 8.
Changing spark plugs is not too hard. Some people do it themselves. You just need a spark plug socket and a bit of patience. But if you’re unsure, go to a mechanic. It’s better to be safe than sorry.
- Spark plugs should be changed between 30,000 to 100,000 miles.
- Signs include poor mileage, hard starts, and shaking.
- Check your manual for exact timing.
- Always replace all spark plugs at once.
- DIY is possible, but a mechanic can help too.
What Happens If You Use the Wrong Number of Spark Plugs
Using the wrong number of spark plugs is a big mistake. Some people think, ‘Oh, 4-cylinder means 4 plugs’ — but that’s not always true. If your engine has 8 spark plugs and you only change 4, you’re only doing half the job.
When this happens, your engine doesn’t run well. Half of the cylinders will get fresh spark, and the other half won’t. This makes your engine misfire, lose power, and shake. You will also waste fuel and can even damage the engine.
One person I know replaced only 4 spark plugs in their Dodge Avenger. The car started to jerk and run badly. He thought something was wrong with the engine. Later, he found out he needed 8 spark plugs. Once he changed all 8, the car ran smoothly again.
If you use the wrong type of spark plugs, that’s also a problem. Always buy the right spark plugs for your car model. Not all spark plugs are the same. Some are longer, some are shorter, and the heat range is different.
- Replacing only half the plugs in a twin spark engine causes misfires.
- Engine may shake, lose power, or burn more fuel.
- Always check how many plugs your engine needs.
- Use the correct type and size for your car model.
- Wrong spark plugs can damage your engine.
Where to Buy the Right Spark Plugs for a 4 Cylinder
Finding the right spark plugs is not hard if you know where to look. You can buy them from local auto parts stores, online shops, or directly from your car’s dealership.
First, check your car’s owner manual to know the exact type and number of spark plugs. Look for the brand, model number, and gap size. Some common brands are NGK, Bosch, Denso, and Champion.
Auto parts stores like AutoZone, Advance Auto Parts, and NAPA can help you find the correct plugs. Just tell them your car’s year, make, and model.
If you want to buy online, websites like Amazon or RockAuto are good options. But make sure to double-check the part number. Online stores sometimes make mistakes in suggestions.
Also, don’t go for the cheapest spark plugs. It might save money now, but cheap ones wear out fast. Always choose good quality.
You can even ask your mechanic to get the spark plugs for you. They usually buy from trusted sources.
- Check the owner’s manual for exact type and number.
- Buy from trusted auto parts stores or websites.
- Use trusted brands like NGK, Bosch, or Denso.
- Avoid the cheapest plugs — they wear out fast.
- Ask a mechanic if you are unsure.
Final Thoughts
Knowing how many spark plugs are in your 4-cylinder engine can save you time, money, and stress. Most of the time, it’s just 4 plugs. But for some cars, it’s 8. Always check your manual, look under the hood, and ask a mechanic if needed. Replacing spark plugs is part of keeping your car healthy. It helps your engine run better and smoother. Don’t wait too long or try guessing — your car depends on the right spark.
| Engine Type | Cylinder Count | Spark Plugs Per Cylinder | Total Spark Plugs | Brands Recommended | Change Interval |
|---|---|---|---|---|---|
| Regular Gas Engine | 4 | 1 | 4 | NGK, Denso | 30,000–60,000 miles |
| Twin Spark Engine | 4 | 2 | 8 | Bosch, Champion | 60,000–100,000 miles |
| Turbocharged Engine | 4 | 1 | 4 | NGK Iridium | 60,000–100,000 miles |
| Sports Engine | 4 | 2 | 8 | Denso Iridium | 80,000–100,000 miles |
Frequently Asked Questions (FAQs)
Is it normal for a 4 cylinder to have 8 spark plugs?
Yes, some 4-cylinder engines are made with 8 spark plugs. These engines use a twin spark system, which means each cylinder has 2 spark plugs. This helps the fuel burn better and makes the engine run smoother. It’s not a problem at all — it’s just a different design. Always check your car manual to be sure how many spark plugs your car has.
Is it bad to replace only 4 spark plugs in a twin spark engine?
Yes, it is bad. If your engine has 8 spark plugs and you replace only 4, the other 4 old ones will not work as well. Your engine may misfire, lose power, and run rough. You should always replace all spark plugs at the same time, so your engine runs evenly and safely.
Can I check spark plugs by myself?
Yes, you can. First, make sure your engine is off and cool. Then open the hood and look for the wires or coils connected to the spark plugs. Count them to see how many spark plugs you have. If you’re unsure, remove the engine cover. You can also use your manual or ask a mechanic.
Can I use any spark plug for my car?
No, you should not use just any spark plug. Every car engine is made to work with a certain type of spark plug. Using the wrong one can damage your engine or make it run badly. Always check your owner’s manual or ask a trusted parts store or mechanic for the right type.
Do I need to gap spark plugs before installing?
Sometimes, yes. Many spark plugs come pre-gapped, but it’s always good to check. You can use a spark plug gap tool to measure the space. If the gap is wrong, the spark won’t fire correctly. This can cause poor engine performance. Always double-check before installing.
Do I need a mechanic to change spark plugs?
Not always. If you have some tools and know how to open your car’s hood safely, you can change them yourself. But if your spark plugs are hard to reach, or if you’re not comfortable, it’s better to let a mechanic do it. It’s a quick job for most cars.
Is it safe to drive with old spark plugs?
It might be safe for a short time, but it’s not good. Old spark plugs can cause your engine to misfire, use more fuel, and lose power. If left too long, they can even damage the engine. It’s best to replace them on time to keep your car running well.
Do I need to replace spark plug wires too?
If your car uses spark plug wires and they are old or damaged, then yes, you should replace them. Worn-out wires can cause poor sparks and engine misfires. Some cars use coil packs instead of wires. Check your manual or ask a mechanic if you’re not sure.