Just over 100k miles do I need to change my spark plugs?

[Clapper66]

Hey,

On my 07 explorer with the 4.0 v6 I broke one 100k in March then needed a oil change. When I took it for the oil change I was told plugs should be changed at 100k witch makes since with wear and tear on them. But do the really need to be changed? I ask that because I just drove from James town NY to albany NY a 350 mile trip and got 22.1 MPG. Just because I got that MPG does that mean there good? Also I have no clue is the previous owner did this before I bought it just over 2 years ago when it has 80k on it

Also how hard is it to change them if I wanted to try my self?

Thanks

 

[TestPoint]

The OEM plugs tend to start missing by the time you get to 100k so I wonder if the PO had already changed them. What was the mileage when you bought the car? They are not difficult to change but because of the question one might think that you had not done it before. If so, there are a number of threads and U-tube videos on the subject.

 

[Clapper66]

There was 79k on it when I bought it

 

[2lungking]

take one out and take a look at it maybe check the gap.

 

[Anime]

MPG is just a rough number and doesn't mean much when it comes to spark plugs.

You'll get higher MPG with the right plugs, but higher may mean more than 22.1 MPG but if you've never had new plugs and don't know what the MPG is with new ones, you have nothing to go by.


One way to check the plugs is just looking at them. Pull off one of the spark plug boots (by the boot, not the plug wire) and look at what brand the plugs are. If they aren't Motorcraft plugs, you can be reasonably sure they were changed.

Look at the base of the plug - the metal part. Is is rusty? Is it REALLY rusty? If they look old, they probably are old.

If they are Motorcraft plugs and the metal base is really rusty, you should at least pull one of the plugs to check the condition of the electrode.

If they are pretty well worn, there's a good chance they are original and were just never changed, and changing them out with new OEM Motorcraft plugs will get you better performance and more MPG.


You can change plugs out yourself if you have the right tools - a 5/8" spark plug socket, a ratchet, and various extensions. If you don't have the tools then it's worth it to buy them, you can spend some $$$ on a decent 3/8" socket set or just buy a ratchet, extensions, and spark plug socket.

If you've never changed spark plugs before then you should watch some YouTube videos on how to do it. It's not too difficult but it's better to learn the techniques and how to do it right than screw something up and have to spend a lot of time to fix it.

 

[Clapper66]

OK thanks well I will probably look into checking them in may once I back home. I live on campus and have no tools

 

[Clapper66]

i just looked on youtube and saw this video for a 02 with a 4.0 v6, the 4.0 vs in the 07 is the exact same motor right?

https://www.youtube.com/watch?v=3PhBA33RloY

if so they are not to bad to get to

i have changed spark plus on atvs and snowmobiles so from what i see its only harder to get to them