How easy is DIY for the spark plugs?

[Ruanas]

I am getting close to 40k miles on my 2.5T and the dealer recommended their replacement today at my 35k oil change. The cost? 407.00 which seems excessive to me. I contacted another shop which did my transmission fluid change and they quoted 227.00. This too seems like a lot when I can buy NKG iridium plugs on RockAuto for $60. What is a fair cost for having the plugs changed? Is there anything else which needs to be done at the same time (coils/boots)? I also thought about buying the plugs and having a mobile mechanic come and swap them as I had this done for the front rotors/pads and it went well. I don't have the tools needed, so with adding that cost to the mix, it may make more sense to have it outsourced. Maybe Callisto will be kind enough to tell me what this would cost at his shop?

On another front, It seems my motor is starting use some oil. I noticed it a couple of thousand miles ago and added oil and it was down a tiny bit 1500 miles later(it never used oil in the past). I asked about the stem seal replacement under warranty today and was told I had to let the oil get low enough for the low oil light to trip so that there was a record of it in the cars computer. Then they will do the replacement. I will keep driving with the fresh oil and see what happens.

2021 CX-5 2.5T

 

[Eazeeette]

Pretty easy.

 

[madar]

Ridiculously easy, just make sure you use a torque wrench. Callisto isn't on this forum. OEM plugs are highly recommended but the others have been working well for people.

 

[Boland01]

We're on our third CX5. Haven't done the ones on our 2023 turbo yet but the other two cars were very easy. Make sure the engine is cold when you do it and I'll second using a torque wrench is good advice.

 

[ADS-B]

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.

 

[leeharvey418]

I have 140,000 miles on my factory spark plugs.

 

[ADS-B]

I have 140,000 miles on my factory spark plugs.

Time for spark plugs replacement! ASAP!

 

[JohnSmith17]

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)

 

[JohnSmith17]

Time for spark plugs replacement! ASAP!

Yeah for real, it's such an easy job and the plugs are only like $40-50.. Why risk it?

 

[RedBaron]

I install them without using a torque wrench. Just make sure to tighten the spark plugs really good.

Ahhh, no. Don't just tighten "really good", you risk damaging the plug, or worse, the head.

If you don't have a torque wrench, you can follow the instructions on the NGK package, which says to insert and hand tighten to the bottom touch point, then use a wrench to turn a further fraction of a turn (like 1/4 or 1/3 - I forget now).

 

[ADS-B]

Ahhh, no. Don't just tighten "really good", you risk damaging the plug, or worse, the head.

If you don't have a torque wrench, you can follow the instructions on the NGK package, which says to insert and hand tighten to the bottom touch point, then use a wrench to turn a further fraction of a turn (like 1/4 or 1/3 - I forget now).

I have a torque wrench. I just choose not to use it because I don't think it's necessary. I've replaced the spark plugs several times on my current car and no issues.

 

[gphin]

I changed mine about a month ago and my local indy, who I've done business with for years, charged $170 for the labor. Bought the NGKs online. The $226 quote you received for labor and plugs seems reasonable.

 

[sm1ke]

Maybe Callisto will be kind enough to tell me what this would cost at his shop?

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.

 

[gphin]

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.

Good tip. Remember that happening back in the days when I used to change my own plugs.

 

[leeharvey418]

Time for spark plugs replacement! ASAP!

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.

 

[ADS-B]

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.

Spark plugs are consumables, like oil filter, air filters, brake pads, tires alternator belt, water pump belt etc etc. You should replace them after a certain number of cycles/hours/miles. In our case this is a screenshot from my 2020 cx-5 owner's manual: