I've been trying to find some reasonably priced copper spark plugs for my '09 w/ 5.7, It wasn't as easy as I thought. The OEM plugs that came on my truck are NGK LZFR5C-11. This is a dealer-only part number, there is no NGK stock number, so you can't yet get these at your local parts store. These have changed from the previous years ('08 etc) as they are a colder plug. If you go to Federal-Mogul's website, the Champion part number that comes up is REC12MC4, stock number 446. But nobody has this plug, can't find it available anywhere.

Denso's site gives K16HPRU-11 as their part number, stock number is 6076. They are around $5, roughly same price as the dealer.

These plugs have all have the following heat ranges: NGK=5, Champion=12, and Denso=16. The '08 and earlier hotter plug has heat ranges: NGK=4, Champion=14, Denso=14.

NGK 4306, or LZTR5A-13, is a 5/8" hex, 14 mm thread, 1" reach, heat range 5. Those are the same as OEM, however, the "-13" signifies a .052" gap (as opposed to .044") , and the "A" specifies a different firing end construction, not sure how much that is an issue. This particular plug has been used quite a lot in DC engines, even spec'd as a colder plug on '08 and earlier 5.7 Hemi's. And although not an exact application, once re-gapped I think is a good fit. They are around $2 and available almost anywhere.

 

replace with platium plugs . changed mine at 45,000 now at 92,000 . Had 1 [plug # 7 foul???] No other problems.

 

There have been a good number of folks who have reported problems with platinums (error codes, etc). This was the motivation to stay with copper.

 

I think those were thr dbl platiums ... As many miles I drive I am going with the regular platiums .

 

Stock ones cost about $60 for a set of 16 at the dealer, hardly worth screwing around trying to find something to fit for that price.

 

Yeah I've heard about issues with the plats as well. I'll be sticking with the coppers when I do mine in about another 10,000 miles.

 

I will put the same plug in it that came from the factory, even if I have to buy at the dealer or online. I am going to do mine at 40k. Manual says 30k, I did my 05 at 30 and they were not that bad, which is why I am going 40. Plus I am keeping my truck until 100k, if I change every 40k I will only need to do it twice vs three times.

 

So I found some online for $1.99 at Advance, then had a $10 off coupon, plus my bank card gave me 5% off. So I ended up paying like $20 for a set. But the LZTR5A-13 did not work. They are for a tapered seat and the stock ones are for a flat seat with a washer. So much for trying to save a buck.....

 

The Platiumn or non Platiumn only involves the TIP of the plug. Both are Copper core. I found out the issues with some plugs are ones that are pulse duration. GM has a TSB on the subject. Has to do with noise bleed over.Engine misfire and CHARGE system issues due to the plug.You can use a FACTORY platinum plug that is a 100,000 miler. Its the plug used in 09 UP 5.7 Durango/Caliper Hybrids. Only sold over the dealer counter at this time. There are post using Auto lite platinums and many others with no issues. The tip is the precious metal for longer wear then a standard plug.

 

Put autolite Plats in my 09 5.7L and have had no problems and MPG has come up .8