How easy is DIY for the spark plugs?

[TheMAN]

I install them without using a torque wrench. Just make sure to tighten the spark plugs really good. If you don't have tools for it, go to O'Reilly and you shouldn't have to spend more than 50$ for tools: you need the special spark plug socket, a ratcheting wrench and extension bar for the spark plug socket. And you also need some metric socket set, the bolts on the coils are either 10mm or 8mm, don;t remember from the top of my head. When you install the new spark plugs, you always start tightening by hand (!) until it stops and only after that you use the wrench, socket, or whatever tool you'll use for tightening. There are plenty of YouTube videos about how to install the spark plugs on a Mazda.

there's no "special spark plug socket"... it's just a 14mm spark plug socket... 14mm spark plugs are very common these days across different brands... it's just something new, that's all

 

[TheMAN]

It's the easiest thing you can do.. Takes like 5-10 minutes if you have all the tools.

Make sure you have the right spark plug socket (and make sure it's magnetic). I have a 5/8" socket that I used on previous cars including a Mazda 3, I thought it would fit.. But nope, it's a 9/16" or 14mm.

Then you just need an extension, socket wrench and torque wrench.

The spark plugs should come pre-gapped so you just pop em in..


These are the ones I bought from Rockauto NGK 94124

Edit: https://www.amazon.com/dp/ (commissions earned)

it doesn't have to be "magnetic"... most spark plug sockets have a rubber insert inside to protect and grip the spark plug... they work decently but do go bad when used a lot with hot spark plugs/engines... magnetic ones work OK and are increasingly common with DIYers, but pros don't use them because the magnets can shatter after repeated uses and cause a major mess and inconvenience while a customer is waiting in the lounge

 

[TheMAN]

Callisto isn't on this forum. In fact I think the account he used to join here was banned a year or two ago.

Changing spark plugs is actually quite easy on this engine. You'll need the following:

Spark plugs x4
1/4" or 3/8" drive ratchet with 6" (or longer) extension
8mm and 10mm sockets
14mm spark plug socket
Torque wrench capable of torquing to 12-15 ft-lb (optional)

I think that's all you'd need. There's a few videos on YouTube that walk you through the process. Here's a more recent one that I found. A note: the right-most (when facing the engine) ignition coil pack has a tube running over it that may make it a little difficult to re-seat the pack over the plug when re-installing it.

Another tip: When torquing down the new spark plugs, it may be a good idea to put a small piece of tape on the socket and the extension, so that they are taped together. This way, the socket will always come off with the extension. There's been a couple of times where the socket didn't want to come off the plug without jiggling it around a bit to free it from the plug.

with cheap sockets/extensions, taping them doesn't sound like a bad idea... if you like to invest in tools, a one piece spark plug socket integrated with extension or locking extensions works way better

 

[TheMAN]

Serious question: why? I have no loss in fuel economy, and the engine runs as well as the day I drove it off the dealer’s lot. I realize that putting raw fuel through the cat is very bad, but the ECM should throw a fault for the mismatch in ratios from the oxygen sensors well before that actually becomes a problem.

you must like driving your car till something breaks and you have to go fix it

if you have to ask why, it seems to me you never saw the "big picture" and thought of what happens when you ignore the generally accepted maintenance intervals and just drive the car till it breaks and replace/repair then:

• worn spark plugs give you bad gas mileage/performance ("obvious" to lots of people)
• worn/bad spark plugs makes the ignition coils work harder, then they eventually overheat and fry themselves
• coil packs are an expensive replacement
• a poor running engine cooks the catalytic converter, which costs more than $1000 to replace and if you're "lucky", and your car isn't 80k miles or 8 years old, you get it replaced under warranty IF your dealer is willing to do it
• a poor running engine chokes it up with a bunch of difficult to remove carbon build up... on direct fuel injected engines, removal is expensive and involving

perhaps you think the maintenance schedule is a "mechanic's scam", out to rip you off and have the dealers make more money (I have a pretty smart friend who used to hang out here who thinks/thought this way, and his cars ran fine with basic minimum budget maintenance, but extending intervals for the rest... until little stupid issues happened and caught up to him, and it ended up costing more to fix)... if this was true, we'll still be stuck with 30k mile spark plug and 3000 mile oil changes... it's there to ensure that your car runs trouble free

when your car breaks, it usually happens at the worst possible time, in the worst possible places... so it's not just a simple inconvenience... is this worth it to you to "defer maintenance" to save a few bucks now, or just do it the right way and do it under your own schedule and terms, which is less inconveniencing?

 

[N7turbo]

Only other tip I can provide is to use a 12-18” bit of spare hose or fuel line that fits on the spark plug stem. Use it to help get the spark plugs started in the head. When I was a teen I cross-threaded a new spark plug when I was changing them in my 97 Nissan pickup. Needed my grandfather to come over and use a tap to fix it. I’ve used a spare piece of hose to install spark plugs now. Stick the hose on the stem, put the spark plug in and get it started in the thread by turning the hose. Pull the hose off, and then use your ratchet with extension to get it seated. Torque wrench to finish. NO anti-seize.

Isn't it easier to feel if you are properly threading something if you use your bare hands? I fear by putting a thick piece of rubber on it I will lose that tactile feedback.

 

[TheMAN]

Only other tip I can provide is to use a 12-18” bit of spare hose or fuel line that fits on the spark plug stem. Use it to help get the spark plugs started in the head. When I was a teen I cross-threaded a new spark plug when I was changing them in my 97 Nissan pickup. Needed my grandfather to come over and use a tap to fix it. I’ve used a spare piece of hose to install spark plugs now. Stick the hose on the stem, put the spark plug in and get it started in the thread by turning the hose. Pull the hose off, and then use your ratchet with extension to get it seated. Torque wrench to finish. NO anti-seize.

Isn't it easier to feel if you are properly threading something if you use your bare hands? I fear by putting a thick piece of rubber on it I will lose that tactile feedback.

just use a proper spark plug socket and extension and you wouldn't need to resort to this shade tree/mcguyver trick...

 

[ADS-B]

there's no "special spark plug socket"... it's just a 14mm spark plug socket... 14mm spark plugs are very common these days across different brands... it's just something new, that's all

Right. Thing is I've never had to use a 14 mm socket for anything so when I decided to change the spark plugs myself I did some preparation, and everybody was talking about the "spark plug socket", not about the 14 mm socket. I did not pay attention too much, just took it as such.

 

[N7turbo]

14mm Magnetic Thin Walled Spark... https://www.amazon.com/dp/ (commissions earned)

 

[ruthrj]

Isn't it easier to feel if you are properly threading something if you use your bare hands? I fear by putting a thick piece of rubber on it I will lose that tactile feedback.

It’s funny you mention that. The hose is what I used to try and get a feel for it threading correctly vs blindly turning a ratchet. On my previous vehicles, the spark plug was always slightly too far down in its recess to turn comfortably with my fingers. The spare fuel line I used was my only means of achieving something resembling that feel vs flying blind at the end of the extension!

 

[ruthrj]

just use a proper spark plug socket and extension and you wouldn't need to resort to this shade tree/mcguyver trick...

Take it or leave it, I found it useful for something I haven’t had to do more than once every 5-10 years. Granted it’ll be more often now with the 2.5T, and I think the spark plugs aren’t seated nearly as far down a tunnel of sorts compared to my previous vehicles.

 

[leeharvey418]

you must like driving your car till something breaks and you have to go fix it…

Again - I have no drop in gas mileage, and my engine is running smoothly. By all indications, neither electrode has started to erode, as I would expect from a platinum/iridium alloy.

What’s the purpose of replacing a “wear item” that is giving no indication of having worn?

 

[ADS-B]

Again - I have no drop in gas mileage, and my engine is running smoothly. By all indications, neither electrode has started to erode, as I would expect from a platinum/iridium alloy.

What’s the purpose of replacing a “wear item” that is giving no indication of having worn?

Preventive maintenance!

 

[TheMAN]

It’s funny you mention that. The hose is what I used to try and get a feel for it threading correctly vs blindly turning a ratchet. On my previous vehicles, the spark plug was always slightly too far down in its recess to turn comfortably with my fingers. The spare fuel line I used was my only means of achieving something resembling that feel vs flying blind at the end of the extension!

no one except novices blindly turn the ratchet with whatever is attached to it to start fastening it... for something like spark plugs in these cars where you can't reach with your bare hands, you turn the socket and/or extension by hand to start the threads, NOT with the ratchet... this method is superior and more reliable in almost every way compared to the hose method

 

[TheMAN]

Again - I have no drop in gas mileage, and my engine is running smoothly. By all indications, neither electrode has started to erode, as I would expect from a platinum/iridium alloy.

What’s the purpose of replacing a “wear item” that is giving no indication of having worn?

so the "engine is running smoothly", so that means there's "nothing wrong"... got it... millions of americans go about their day eating junky food, and "feel great", so they don't go to the doctor and get checked up, because there's "nothing wrong"... you can't "see" high cholesterol or heart disease until it's too late

just because you don't see it, doesn't mean there's no problem

I stand by my statement that you must like driving your cars till it breaks before you do something, rather than doing routine maintenance

that factory original denso iridium plug came out of our corolla at 105k miles... toyota recommendation is 120k miles... car ran fine with "no drop in gas mileage"... no check engine light, no codes, no rough idle, no out of ordinary issues... you want to bet 20 bucks that yours looks worse than that?

 

[N7turbo]

It’s funny you mention that. The hose is what I used to try and get a feel for it threading correctly vs blindly turning a ratchet. On my previous vehicles, the spark plug was always slightly too far down in its recess to turn comfortably with my fingers. The spare fuel line I used was my only means of achieving something resembling that feel vs flying blind at the end of the extension!

I see, so we're on the same page then.

 

[ruthrj]

no one except novices blindly turn the ratchet with whatever is attached to it to start fastening it... for something like spark plugs in these cars where you can't reach with your bare hands, you turn the socket and/or extension by hand to start the threads, NOT with the ratchet... this method is superior and more reliable in almost every way compared to the hose method

Never thought a fairly common tip would be that controversial but there’s always one in the bunch. Pretty hard to crossthread a spark plug on the end of a hose is all I’m saying. Good risk mitigation for first timers asking how difficult it is to replace spark plugs. Let’s remember who we are here to help: novices. I turned that rachet blindly a couple decades ago and thankfully had family to help me out.

Another added to the ignore list.

 

[leeharvey418]

My position was that I don’t see the sense in doing something for no better reason than “the manual says so”.

I found the reason - high-resistance plugs make ignition coils run hotter, and that can lead to sudden failure of the coil, which can precipitate a quick failure of the catalytic converter.

I asked a simple question, and got a lot of condescending answers. Sorry for overtaxing everyone’s knowledge base.

 

[TheMAN]

Never thought a fairly common tip would be that controversial but there’s always one in the bunch. Pretty hard to crossthread a spark plug on the end of a hose is all I’m saying. Good risk mitigation for first timers asking how difficult it is to replace spark plugs. Let’s remember who we are here to help: novices. I turned that rachet blindly a couple decades ago and thankfully had family to help me out.

Another added to the ignore list.

there's nothing "controversial" about it.. I didn't say it doesn't work... I just said it's not needed when you use a socket and extension to start the threads, not start wrenching it down with a ratchet... that was proper advice to help novices here, but you thought I was telling everyone to make the same mistake you did or were too offended to see that

 

[TheMAN]

My position was that I don’t see the sense in doing something for no better reason than “the manual says so”.

I found the reason - high-resistance plugs make ignition coils run hotter, and that can lead to sudden failure of the coil, which can precipitate a quick failure of the catalytic converter.

I asked a simple question, and got a lot of condescending answers. Sorry for overtaxing everyone’s knowledge base.

ahh, so you do think the maintenance schedule is a "mechanic's scam", out to rip you off and have the dealers make more money... unlike what some shady mechanics might tell you, the manufacturer's maintenance schedule is generally written to help you achieve long life of the car, not out to scam you of your money or any other reason "the manual says so"... it doesn't even say you must go to the dealer to maintain it, merely recommends it for the (generally) best possible service... where you do your service, is all left to you and it still recommends using genuine mazda parts to ensure no issues

 

[ADS-B]

My position was that I don’t see the sense in doing something for no better reason than “the manual says so”.

I start to think that you are playing the devil's advocate and you enjoy reading all the comments here trying to convince you to do something that you know it's good for your car and for your pocket.