Mazda 3: Change Spark Plugs and Air Filter - May 9/15
I found this post online and decided to incorporate it into my blog. I changed my spark plugs too, at 67K. All 4 plugs were worn and dirty, similar to the ones in the photos below. My air filter was extremely dirty, full of bugs and shit.
Next, a note about gapping the plugs. "Gapping" refers to adjusting the ground electrode on the end of the plug to be a specific distance away from the center electrode, to produce a spark of a size within the specifications defined by the car's manufacturer. What it boils down to is this: if you buy the NGK plugs listed above, they come pre-gapped from the factory at a distance that falls within Mazda's spec. If you decide to buy different plugs, you may need to gap them. There are numerous tutorials online that explain the simple process of gapping spark plugs, and the tools needed to do so.
I'd also recommend getting a tube of anti-seize for the threads, to make it easier the next time you need to replace the spark plugs. Anti-seize should cost about $3.50 from any auto parts store.
So let's get started:
1. Pop the hood, and remove the engine cover. Just pull up from the edges and it'll unclip.
2. The Mazda3 uses a coil-on-plug design, meaning there's no distributor or spark plug wires. Each spark plug gets its own coil pack, which plugs right on top of it. Each coil pack is secured with a single bolt. Note that two of the bolts have black plastic studs screwed on to them; these studs are for clipping the engine cover down. The coil packs are circled in red below, and the bolts are in blue:
3. I recommend replacing only one spark plug at a time. With your 8mm wrench or deep socket, remove the first coil pack bolt:
To remove the plastic studs from two of the bolts, use a 15mm wrench to unscrew it, then you can use the 8mm wrench/socket to remove the bolt:
4. With the bolt removed, the coil pack just pulls up from the spark plug. You shouldn't need to disconnect any cables, just swivel the coil pack out of the way. The plug sits at the bottom of the spark plug tube; here's a view of the tube with the coil pack removed:
5. Use the 5/8" spark plug socket, extension and ratchet wrench to remove the old spark plug. The spark plug socket has a rubber grommet in it that will hold onto the spark plug as you remove it, so it won't fall back in. Here's what your old spark plugs are likely to look like (these are my factory plugs with about 68k on them):
| Report this image |
Next, a note about gapping the plugs. "Gapping" refers to adjusting the ground electrode on the end of the plug to be a specific distance away from the center electrode, to produce a spark of a size within the specifications defined by the car's manufacturer. What it boils down to is this: if you buy the NGK plugs listed above, they come pre-gapped from the factory at a distance that falls within Mazda's spec. If you decide to buy different plugs, you may need to gap them. There are numerous tutorials online that explain the simple process of gapping spark plugs, and the tools needed to do so.
I'd also recommend getting a tube of anti-seize for the threads, to make it easier the next time you need to replace the spark plugs. Anti-seize should cost about $3.50 from any auto parts store.
| Report this image |
So let's get started:
1. Pop the hood, and remove the engine cover. Just pull up from the edges and it'll unclip.
| Report this image |
2. The Mazda3 uses a coil-on-plug design, meaning there's no distributor or spark plug wires. Each spark plug gets its own coil pack, which plugs right on top of it. Each coil pack is secured with a single bolt. Note that two of the bolts have black plastic studs screwed on to them; these studs are for clipping the engine cover down. The coil packs are circled in red below, and the bolts are in blue:
| Report this image |
3. I recommend replacing only one spark plug at a time. With your 8mm wrench or deep socket, remove the first coil pack bolt:
| Report this image |
To remove the plastic studs from two of the bolts, use a 15mm wrench to unscrew it, then you can use the 8mm wrench/socket to remove the bolt:
| Report this image |
4. With the bolt removed, the coil pack just pulls up from the spark plug. You shouldn't need to disconnect any cables, just swivel the coil pack out of the way. The plug sits at the bottom of the spark plug tube; here's a view of the tube with the coil pack removed:
| Report this image |
5. Use the 5/8" spark plug socket, extension and ratchet wrench to remove the old spark plug. The spark plug socket has a rubber grommet in it that will hold onto the spark plug as you remove it, so it won't fall back in. Here's what your old spark plugs are likely to look like (these are my factory plugs with about 68k on them):
| Report this image |
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