Motorcraft SP432 plug life expectancy?

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Sep 27, 2015
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Alabama
2002 Ford Ranger Edge 3.0L 85k

Just curious as to what the mileage life expectancy of these plugs are? I have looked online and a few articles point to 20kish miles while others in forums have reported as far as 40k with them. These are the OEM plugs that my truck calls for, however, I was wondering if NGK makes a better plug in terms of life span? I am a huge advocate for OEM parts when it comes time to replace them as it has always served me well and if time and circumstances allow for it.

edit: I do understand that driving habits typically play into stuff like this and my truck is running great as of right now with about 19kmiles on the plugs listed in the title. No real reason to try NGK or any other brand outside of curiosity.
 
I had a ‘91 Ranger with the same engine. It came with Platinum plugs and the manual called for 100,000 mile changes. I changed mine at 50,000 miles. If it’s running good, I would wait until you get some more miles accumulated.
 
Years ago when straight copper plugs were used the agreed mileage (and was stated in the owners manual) to change them at 30k miles. Half the plugs I took out at that mileage needed replacing and the other half could have gone longer.

My 2005 Ranger, same as yours, came from the factory with Platinum plugs and the OM said they were good for 100k. I pulled them at 75k for a check and they were toast. I'm now using the straight copper plugs, like you, and will keep an eye on them. I'm not sure what to expect on their life expectancy. So I'm expecting, and hoping for 30k.

I would have thought with unleaded fuel, better spark intensity and cleaner burning engines that copper plugs would last longer than days of old. We will see but after the disappointment with the Platinum's I'm not so sure.

Ours is a waste spark system that seems to erode the center conductor quicker that other ignition systems.

EDIT: Like you, I stick with OEM parts!
 
No, just an experiment. I tried Denso Iridium's, thinking they would easily make 100k, and took a look at them at 20k. The left bank (the waste spark side) center electrode was completely gone. Melted away. That is when I just threw in the coppers. If they don't last I'll go back to Platinum's.
 
Op - I have the same Ford Ranger 3.0L as you.

My original Plugs were changed at 99,000 miles / as per Service Manual
Replacements were Motorcraft Platinum SP-342 which lasted 38,000 until I had Engine Code PO300 and PO304

My next replacement was Autolite XP-104 Iridium / so far 25,000 miles and no problems.
Once I get 50,000 miles on them, I'll pull and inspect.

Lets talk wires,
Originals were changed at 99,000 miles
Replacements (Duralast from AZ) lasted 38,000 miles
My next replacement was OEM / so far 25,000 miles and no problems.
 
Op - I have the same Ford Ranger 3.0L as you.

My original Plugs were changed at 99,000 miles / as per Service Manual
Replacements were Motorcraft Platinum SP-342 which lasted 38,000 until I had Engine Code PO300 and PO304

My next replacement was Autolite XP-104 Iridium / so far 25,000 miles and no problems.
Once I get 50,000 miles on them, I'll pull and inspect.

Lets talk wires,
Originals were changed at 99,000 miles
Replacements (Duralast from AZ) lasted 38,000 miles
My next replacement was OEM / so far 25,000 miles and no problems.
I replaced the wires with OEM as well about a year and a half ago. The lady that owned the truck before me had some shade tree guy throw some no names on there. Wasn’t causing a problem, but it bothered me and my OEM ocd lol
 
Try NGK Laser Platinum or Laser Iridium. These are the extended life plugs.
These were the ones I was looking at when I decided to post the thread. I’ll keep an eye on my current plugs and see how they fair for a bit then decide if I want to pull the trigger on the NGK’s.
 
Iridium will last longer than platinum. NGK Laser Iridium, Denso Iridium Long Life, and Denso Iridium TT are all great options.

NGK makes ruthenium which is supposed to last even longer
 
My former C-Max Energi came with Motorcraft Iridium plugs, I had two plug failures by 45K despite the engine not running more than 40% of the time. I switched to NGK and didn’t have any issues through 88K which is when I got rid of the car.
 
I thought the manual on the Ranger 3.0 calls for a standard copper plug with a 50,000km service interval? At least that's what my 2008 manual says. Would the upgraded platinum or iridium plugs cause extra stress on the coil pack? These coil packs are notorious for cracking and failing.
 
^ AFAIK, Ford has been using platinum or better for 25 years.

I looked in the 08 Ranger Owner manual and it states to refer to the scheduled maintenance manual, which states normal service is 90K mi, excessive idling traffic/commercial/etc use, 60K mi.

The SP432 are "about" 100K mi plugs and unless the engine was abused, they last "about" that on average in a new engine.

The older the engine gets, especially hard miles or less than optimal maintenance, the shorter the lifespan of the new plugs.

Since plugs aren't expensive, I'd replace platinum or better, every 50K mi after that unless they are hard to access (requiring intake/etc disassembly which is more common with transverse V-engine configurations), then waiting for a reason to change or at least check them (then you might as well replace them while they're out) up until 90K again.
 
I thought the manual on the Ranger 3.0 calls for a standard copper plug with a 50,000km service interval? At least that's what my 2008 manual says. Would the upgraded platinum or iridium plugs cause extra stress on the coil pack? These coil packs are notorious for cracking and failing.
My 2002 Ford Ranger came with Platinum plugs.
161,000 on 'original' Coil Pack.
 
I've ran several sets of Bosch Platinum plugs between 100-125K miles. They were still firing fine when I changed them. The only reason I changed them was because I felt guilty they'd been in the car so long. I've been using Bosch Platinum plugs for about 30 years and have never changed a set with less than 100K miles. The only one I've ever had a misfire on was when I'd had the plugs out for a compression test if I recall correctly and put them back in I had a miss. Upon taking the plugs back out I found one with a broken insulator which was probably my fault.
 
Try NGK Laser Platinum or Laser Iridium. These are the extended life plugs.
Yep - NGK’s G-Power and Iridium IX as well as Denso’s Iridium Power are single-tip “performance” spark plugs. The Laser series for NGK and Long Life/TT series at Denso are OEM-type double precious metal(for the exception of a titanium alloy ground pad on the Platinum TT).
 
NavyVet88 - Another thing I had a problem with on my '02 Ranger;

For several years I noticed Coolant drops on the hood and could NEVER find the source.
It ended up being the PLASTIC Tee-Fittings in the Heater-Core Hoses were cracking.
The 'leak' finally became noticeable, and I replaced them (at 161,000 miles).
 
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