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Saturday, December 15, 2012

Change your spark plugs

Tools Required
- 8mm regular socket
- 10mm regular socket 
- 12mm regular socket
- 5/8ths spark plug socket (magnetic is helpful)
- 3/8ths Drive Ratchet for attaching your sockets
- 3" or 6" extension for your ratchet & sockets
- Phillips screwdriver

Materials Required
- New spark plugs (using Denso ITV22 plugs in this example)

- Anti-seize
- Spark plug gap gauge tool 

To get started, pop open your hood.  Remove the top cover of the battery box by gently pulling the plastic latches on the sides of the box.

Using a ratchet and 10mm socket (or 10mm wrench), disconnect the negative lead from the battery.  This is the terminal closest to the firewall and has 2 black wires.  Be sure not to touch the positive terminal with your tools while you are removing the negative.  Set the negative lead to the side. 

With your ratchet and 10mm socket, remove the 2 bolts on the intercooler cover.

To remove the intercooler, remove the 3 12mm nuts with a socket (shown in the picture) and disconnect the bypass valve by using a 10mm socket to remove the bolts.  Next, using a phillips screwdriver, remove the 2 hose clamps shown in the photo below.  After all of these connections have been removed, take off the intercooler.

Grab your 8mm socket with an extension and attach it to your ratchet.  Remove the 4 bolts that hold the valve covers and spark plug wires.

Pull out the spark plug wire, attach your 5/8ths spark plug socket and remove the spark plug.

Open your new spark plugs and ensure that they are all gapped properly by using a gap gauge/feeler.  In this example, I'm measuring all 4 plugs for a .028" gap.

Before putting the new plugs back in place, I liberally applied some anti-seize at the top of the threads so that the plugs will be easy to remove when they need replacing.

Now, just work backwards.  After you've installed the remaining plugs, re-connect the following:
- the spark plug wires, fasten with 8mm bolt
- replace the intercooler, connect it to the 2 hoses, tighten the hose clamps with a phillips screwdriver
- reconnect the bypass valve to the intercooler, tighten the 2 10mm bolts
- secure the intercooler by tightening the 3 12mm nuts
- place the intercooler cover on top of the intercooler, secure with the 2 10mm bolts
- reconnect the negative battery lead to the terminal
- replace the battery box cover 

NOTE: Because your battery was disconnected, your auto window up/down function may not work.  Roll the window all the way down by using the switch, then pull the window switch back up until it clicks and roll the window up all the way.  Auto window up/down should now work


Parker said...

what plugs do you recommend? also when I pull the intercooler off, will anything spill out?

jimmy said...

Most Mazda forums recommend using the OEM plugs as they are high quality (NGK iridium).

Nothing should come out if the intercooler except air :)

Andrew Heffron said...

I love how each plug cover has a number 2 on it... Arigato, Mazda.

Andrew Heffron said...

Good How-To. One thing, though: You don't need to disconnect the battery, there's no juice going to the plugs with the engine off. Even if there was, the design of the plug boot makes it pretty much impossible to get zapped.

Andrew Watt said...

What is the proper torque specification for tightening the plugs in? You didn't use a torque wrench?!

Andrew Watt said...

What is the proper torque specification for tightening the plugs in? You didn't use a torque wrench?!

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