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V8 Spark Plug Maintenance Interval

7K views 18 replies 11 participants last post by  peckmv 
#1 ·
For my 011' GC, Chrysler recommends changing the spark plugs at 36K mile intervals, while the V6 interval is 100K. Does anyone know why? I am up to almost 100K on the original plugs on my 04' 4.7 V8 with no issues.
 
#2 ·
Your stock plugs are copper and you will definately notice improved performance after replacing them at 100K. Replace them with the stock Champions and you'll be happy you did;)

I'm assuming that the V6 utilizes a longer life plug. Hence, the extended replacement interval.
 
#3 ·
Most newer engines use a platinum plug which will last longer. Also be careful on the 4.7, if they are in there too long you will not have fun trying to get them out without breaking them.
 
#10 ·
This topic was covered a month or so ago. Champion makes a 9055 Iridium plug to fit the 2011-12 HEMI. Intial cost is higher than copper, but the plugs have a 7 year, unlimited mile warranty. Change out the copper plugs at 36,000 for improved mileage and performance.
I also went to the NGK site and they spec a platinum plug along with the standard copper plug. The difference in cost is not much, so its a nobrainer. I was just wondering if for some reason the platinum couldn't be used in the hemi. The shocker for me is the cost of the diff fluid. Its like $40+ per quart. I heard its made by Castrol for Mopar. I plan on doing some more research to find a suitable replacement for the Mopar brand.
 
#9 ·
the best spark plugs ar E3 Spark Plugs..IMO...I just got sponsored by them and installed my set of E3 and trust me you will notice a difference in milage and performance.
 
#13 ·
The HEMI is installed in RAM trucks as well as other vehicles. Apparently the installation of 16 copper plugs saves the Chrysler/Fiat on the assembly line. But it's a great reason to bring the vehicle in at 36,000 so they can check out the vehicle for other services. The E3 plug is all hype. Ask them to show the dyno testing. The massive ground electrode glows in the heat unlike the the copper cored ground electrode on the Champion 9055. I'd want the hottest part of the spark plug to run as cool as possible for better performance and longer life.
 
#14 ·
Chrysler runs extensive durability tests on their engines. They will recommend maintenance intervals based on their testing.

Chrysler makes no extra money when spark plugs are changed out, so I doubt there is any conspiracy going on here.

The maintanance costs were one of the reasons that when I traded in my Hemi, I chose to replace it with the much improved V-6. Even the oil changes are less demanding, and the filter, mounted high up on the front of the engine, makes do it yourself changes a snap.
 
#15 ·
IIRC - the SRT version of the HEMI uses the big ticket (platinum/whatever) plugs and has maintenance intervals similar to that of the Pentastar
 
#16 ·
The copper plugs are not only the cheapest, but have the best spark = better performance. I'm o.k. with changing them out every 30K, for those who have changed them out for longer life plugs have noticed a dip in performance and sometimes a rough idle. This is a case where the stock units work the best...
 
#18 · (Edited)
Beg to disagree, but copper cored plugs don't fire better. The spark is erratic firing all around the square ground wire. The Champion Iridiums along with Double Platinums have Trapezoidal ground wires along with the finer wire center electrode. That focuses the spark to one point on the ground electrode for better performance and idle stability. You should see the smoother firing pattern on an a oscilloscope and results on the dyno.
 
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