Spark Plug Replacement

Joined
Jun 11, 2003
Messages
1,041
Location
Hedgesville, WV
This seems like a silly question even to me but I thought I would get your opinion. I have a 2012 Ford Fiesta S that has 65k miles and thought maybe its time for new plugs as the service manual calls for them at 60k. Today I pulled 1 to get the part # and to check its condition. They are iridium made by NGK with a Ford PN on them. It looks clean and in good condition other than the gap has opened just slightly from .031 to .0335. With a normal copper plug I would just regap but copper plugs dont normally stay this long in a motor. If they were $2 ea I would just replace but the Ford part is 11.50 and the NGK part is 10.65 that and I dont know how long they can stay in before I start risking them seizing if ever.
Do you think I should just run them till I notice a problem or replace them by the book. NGK calls them 100k plugs.
 
Joined
Dec 19, 2019
Messages
3,883
Location
Muncie, Indiana
I'd say look for Delco plugs, because they tend to be rebranded NGK Laser Iridiums too, and they usually are cheaper and have a rebate. but doesn't look like there's a Delco iridium plug for this car.
 
Joined
May 9, 2014
Messages
2,183
Location
Minnesota
This seems like a silly question even to me but I thought I would get your opinion. I have a 2012 Ford Fiesta S that has 65k miles and thought maybe its time for new plugs as the service manual calls for them at 60k. Today I pulled 1 to get the part # and to check its condition. They are iridium made by NGK with a Ford PN on them. It looks clean and in good condition other than the gap has opened just slightly from .031 to .0335. With a normal copper plug I would just regap but copper plugs dont normally stay this long in a motor. If they were $2 ea I would just replace but the Ford part is 11.50 and the NGK part is 10.65 that and I dont know how long they can stay in before I start risking them seizing if ever.
Do you think I should just run them till I notice a problem or replace them by the book. NGK calls them 100k plugs.
they are not going to seize if you just took them out.
 
Joined
Mar 31, 2019
Messages
360
Location
Minnesota
Had this issue with both my recent used car purchases, the plugs I took out were maybe 50k into use, but could likely go another 50k, obviously top of the iridium line NGK and Denso. I've put anti-seize on them in a light coat and reinstalled them. I'll probably change them in another 30k. I prefer the anti-seize as it does take a little working back and forth to get them out at this mileage and it ain't going to get better over time.
 

samven

Thread starter
Joined
Jun 11, 2003
Messages
1,041
Location
Hedgesville, WV
Thanks guys, I was leaning towards just running them. I am guessing that the threads must have a factory coating to help avoid seizing. The worst looking part of the plugs were the threads, they were dark but threaded out smoothly with enough resistance to work the ratchet for the first 3 or 4 turns, after that just fingers.
 

blupupher

Site Donor 2021
Joined
Aug 27, 2004
Messages
7,451
Location
Katy, Republic of Texas
I changed the plugs in my mom's Saturn Vue @ 130,000 miles, and the fine wire plugs still looked fine.
I could have kept using them if I needed to, but changed them. Vehicle ran no different with the new plugs.
 

samven

Thread starter
Joined
Jun 11, 2003
Messages
1,041
Location
Hedgesville, WV
if i remove them, then i change them, just me that's all folks
Believe me if this was my Ram truck I would not even dream of trying to get them out if I was not replacing them but the Fiesta has them sitting right on top in a row with no covers. And the 16 copper cores in the truck cost less than the 4 Iridium's in the Fiesta.
 
Joined
Dec 8, 2011
Messages
895
Location
MO, USA
It's been more than a minute since a scope as my friend, but I here you. My Girl Friend, not my GF has a Town and Country van 2008 I bought her plugs, injector cleaner and Air Filter, she lost the cleaner and the Air Filter already. Then she gets snarky about changing the wires. So the van is showing mis-fires which the plugs will fix. But her phone is off no money to add time and I'll be ****ed if i am buying wires she does not need. I also bought her antifreeze, which has since leaked out so she added water, you simply can not tell her that the calcium in tap water will ruin the water pump seal and eventually the pump bearing !!
 
Joined
Jul 11, 2021
Messages
939
Location
Close to Sierra mountains
It's been more than a minute since a scope as my friend, but I here you. My Girl Friend, not my GF has a Town and Country van 2008 I bought her plugs, injector cleaner and Air Filter, she lost the cleaner and the Air Filter already. Then she gets snarky about changing the wires. So the van is showing mis-fires which the plugs will fix. But her phone is off no money to add time and I'll be ****ed if i am buying wires she does not need. I also bought her antifreeze, which has since leaked out so she added water, you simply can not tell her that the calcium in tap water will ruin the water pump seal and eventually the pump bearing !!
partspro.... interesting did you get that title at one of the chain stores?

I hear ya about helping friends and relatives. Anymore I just say IDK ????
 
Joined
Dec 22, 2002
Messages
4,743
Location
The Garden State
From a wear standpoint at 60,000 miles the factory iridium plugs were like almost new in our 2.3 EB Explorer. But I didn't want them to be seized when I needed to change them at 100,000 miles. During removal they were real tight and "squeaky", not a good feeling with an aluminum head. I got the replacement iridium Motorcraft plugs from Rock Auto for less than $5 each. I used anti seize on the threads and torqued to 15% less than specs. I'll leave them alone for an additional 100,000 miles now.
 
Joined
Mar 20, 2008
Messages
14,120
Location
USA
FWIW, Rock Auto has Denso TT for $6 each, and the OE Motorcraft NGK for $7 each :)

But you don't need to replace them until 100k, which is why they cost so much :sneaky:
 
Joined
Jul 11, 2021
Messages
939
Location
Close to Sierra mountains
Ya well the anti-seize information usage came about because DIY will be DIY and will destroy installing a car scent. LOL
I realize that some manufactures offer a so called protective coating that REDUCES (make smaller or less in amount, degree, or size.) the changes of burguring up a thread and also head damage due to several reasons but I have yet to see a long tested result having used these spark plug that indicate there total worth? And I still get at least a few times a year someone that tries to change their plugs that the spark plug thread has caused damage to the threads even with the "better" spark plugs. Oh and when someone brought their engine to me for a rebuilt the customer was handed gloves and tools for them personally to first remove the spark plugs from the head. I wonder why I had them do that? LOL
I might add if you reduce the torque of a spark plug based on the use of anti seize you are likely using to much anti seize and you could under some condition blow the plug right out of the cylinder head.
And I have to laugh again at people who look at a spark plug and if it resembles a chart or they think is looking good has the any idea the wave form and how the spark plug is actually performing?? Hmmm maybe they use an 8 ball for their questions. I do sometimes. ;)
You all realize that spark plug tip temperature and firing result in what the end appearance can be.
And for the engineers maybe some of you look up the properties of these coating applied to spark plug from the spark plug manufactures? :)

Ignition of the fuel(gasoline) in the cylinders produces temperatures of 700°C or more.






What no Beetle owners around this forum? HA!

Magic_8_ball_outlook_not_good.jpg
 
Last edited:
Top