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Discussion Starter #1
Hello forum,

I just bought a '05 300C with the 5.7 Hemi engine. I have to replace the spark plugs, the spark plug wires and the EGR valve. I was wondering (especially for the valve) if I should go for the mopar parts, or if buying some other, much cheaper brands (on rockauto.com) was fine. I was also planning on buying iridium spark plugs since they last longer.

Thoughts?

Thank you!
 

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Hello forum,

I just bought a '05 300C with the 5.7 Hemi engine. I have to replace the spark plugs, the spark plug wires and the EGR valve. I was wondering (especially for the valve) if I should go for the mopar parts, or if buying some other, much cheaper brands (on rockauto.com) was fine. I was also planning on buying iridium spark plugs since they last longer.

Thoughts?

Thank you!
All depends on your cash flow. Remember you have 16 plugs which can get a bit expensive.

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Discussion Starter #3
All depends on your cash flow. Remember you have 16 plugs which can get a bit expensive.

Sent from my SM-G975U using Tapatalk
Well the irridium plugs supposedly last about 4x as long as the copper ones and cost like... 3-3.5x the money so in the end the ratio is a win. I'm really wondering about the egr valve and the plug wires though. Because the mopar valve and the mopar wiring are like 150 CAD each while the non-mopar brand ones are like ~50 CAD each.

But I don't wanna pay 50$ for them and be stuck replacing them again in three weeks, y'know?
 

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Well the irridium plugs supposedly last about 4x as long as the copper ones and cost like... 3-3.5x the money so in the end the ratio is a win. I'm really wondering about the egr valve and the plug wires though. Because the mopar valve and the mopar wiring are like 150 CAD each while the non-mopar brand ones are like ~50 CAD each.

But I don't wanna pay 50$ for them and be stuck replacing them again in three weeks, y'know?
I did aftermarket EGR but forgot the name brand. All I know is that my mechanic said it was a reputable company. (Which is no help to you, sorry)

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Discussion Starter #5
I did aftermarket EGR but forgot the name brand. All I know is that my mechanic said it was a reputable company. (Which is no help to you, sorry)

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Would it be WVE or Standard Motor Products by any chance? (The two non-mopar options available on Rockauto.com :V )
 

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Welcome to the forum. Some of the different Chrysler product forum members have indicated that the aftermarket EGR Valves are sort of hit and miss. If you can get the OEM type from RockAuto, that would be my first choice, if the price isn't outrageous like most Mopar stuff. My second choice would be an aftermarket unit from one of the major parts manufacturers. Most, if not all of the valves are likely made in China anyway. All this being said, when I did mine about 9 years ago, I used an aftermarket valve and it's been fine. Even if you had to do the job twice because of a bad one, it's not that tough a job.

As far as spark plugs goes, the Factory Service Manual recommends nothing but copper core plugs for the early 5.7 Hemi's. I have two 5.7's and use nothing but NGK copper core plugs in both. Some folks have tried using platinum or iridium plugs and, at some point have ended up with misfires, especially in some of the 07's. On this one, I'd say use the platinum/iridium ones at your own risk. I have Sultans of Spark (SOS) coils on both of mine and run a wider spark plug gap than stock. In my 05, I have tried NGK platinum, gapped to the stock settings without issue. I only ran them for about 1500 miles and then went back to the copper core. Plugs on the LX vehicles are also not that tough a job, just twice the number of them than a lot of older vehicles. When you change them, no matter which type you use, be sure to torque them properly and DO NOT use any anti-seize compound on NEW plugs.

Now to your spark plug wires, if you're going to change them. If you don't necessarily want to change them, check them, end to end with an ohm meter. All the wires are about 3 feet long and the rule of thumb is no more than 10000 ohms per foot. Also, carefully inspect the insulation for brittleness and/or cracking. A new stock wire should run between 12000-18000 ohms over the full length.....considerably less than the maximum. If you end up changing them, I'd recommend you dump the "rat's nest" (Chrysler's failed Wasted Spark Setup) that goes for the top of the engine and switch over to something like Taylor Shorty Wires. This will make your setup almost like the 2006 and up Hemi vehicles, except you'll still be using the stock 05 coils that only cover one of the plugs on each cylinder. Over the past 15 years with my 05, I've used the stock Wasted Spark setup that came with the vehicle, both home made and Taylor Shorty wires and finally I changed the whole system over to the 06 and up Hemi's when I added the SOS coils. I've never had a problem with any of them, but I am pretty anal about preventative and scheduled maintenance because I tend to keep my vehicles almost forever.

Good luck on your repairs and let us know how it goes and what all you ended up doing.
 

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Welcome to the forum. Some of the different Chrysler product forum members have indicated that the aftermarket EGR Valves are sort of hit and miss. If you can get the OEM type from RockAuto, that would be my first choice, if the price isn't outrageous like most Mopar stuff. My second choice would be an aftermarket unit from one of the major parts manufacturers. Most, if not all of the valves are likely made in China anyway. All this being said, when I did mine about 9 years ago, I used an aftermarket valve and it's been fine. Even if you had to do the job twice because of a bad one, it's not that tough a job.

As far as spark plugs goes, the Factory Service Manual recommends nothing but copper core plugs for the early 5.7 Hemi's. I have two 5.7's and use nothing but NGK copper core plugs in both. Some folks have tried using platinum or iridium plugs and, at some point have ended up with misfires, especially in some of the 07's. On this one, I'd say use the platinum/iridium ones at your own risk. I have Sultans of Spark (SOS) coils on both of mine and run a wider spark plug gap than stock. In my 05, I have tried NGK platinum, gapped to the stock settings without issue. I only ran them for about 1500 miles and then went back to the copper core. Plugs on the LX vehicles are also not that tough a job, just twice the number of them than a lot of older vehicles. When you change them, no matter which type you use, be sure to torque them properly and DO NOT use any anti-seize compound on NEW plugs.

Now to your spark plug wires, if you're going to change them. If you don't necessarily want to change them, check them, end to end with an ohm meter. All the wires are about 3 feet long and the rule of thumb is no more than 10000 ohms per foot. Also, carefully inspect the insulation for brittleness and/or cracking. A new stock wire should run between 12000-18000 ohms over the full length.....considerably less than the maximum. If you end up changing them, I'd recommend you dump the "rat's nest" (Chrysler's failed Wasted Spark Setup) that goes for the top of the engine and switch over to something like Taylor Shorty Wires. This will make your setup almost like the 2006 and up Hemi vehicles, except you'll still be using the stock 05 coils that only cover one of the plugs on each cylinder. Over the past 15 years with my 05, I've used the stock Wasted Spark setup that came with the vehicle, both home made and Taylor Shorty wires and finally I changed the whole system over to the 06 and up Hemi's when I added the SOS coils. I've never had a problem with any of them, but I am pretty anal about preventative and scheduled maintenance because I tend to keep my vehicles almost forever.

Good luck on your repairs and let us know how it goes and what all you ended up doing.
Wow. Thanks for the very clear and elaborate response! Though why shouldn't I use anti-seize on new plugs? Every tutorial and the service manual (I think) recommend it!
 

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Just about all the new spark plugs come with a nickel plating which is the anti-seize. If you remove the plugs and reinstall the same ones, then use a SMALL dab to keep them from seizing. So, if your plugs are silver (nickel plated), don't use anti-seize on a NEW install. Here's a few references for you:

Two Common Lubricants - Anti-Seize & High Temperature Synthetic Lube (Read the warning under, "NOTES".


Champion - A Complete Guide To Spark Plug Performance (Read the "Installation Tips".

Also, if you're going to use the "factory recommended" Champion plugs for the 5.7's be sure to use ONLY the black tip ones. There are two different Champion spark plugs with the same part number, but are considerably different....the black tip ones and the silver tip ones. This difference was the cause of some of the 07 5.7 Hemi stalling/misfiring problems. Here's a chart showing the differences between the two. Who makes to vastly different spark plugs with the same part number......Champion. That's the main reason I use NGK.

 

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Just about all the new spark plugs come with a nickel plating which is the anti-seize. If you remove the plugs and reinstall the same ones, then use a SMALL dab to keep them from seizing. So, if your plugs are silver (nickel plated), don't use anti-seize on a NEW install. Here's a few references for you:

Two Common Lubricants - Anti-Seize & High Temperature Synthetic Lube (Read the warning under, "NOTES".


Champion - A Complete Guide To Spark Plug Performance (Read the "Installation Tips".

Also, if you're going to use the "factory recommended" Champion plugs for the 5.7's be sure to use ONLY the black tip ones. There are two different Champion spark plugs with the same part number, but are considerably different....the black tip ones and the silver tip ones. This difference was the cause of some of the 07 5.7 Hemi stalling/misfiring problems. Here's a chart showing the differences between the two. Who makes to vastly different spark plugs with the same part number......Champion. That's the main reason I use NGK.


Thanks for your help. I didn't know about the black tips! Anyway, the plugs I'm buying, according to the picture on Rockauto, do have the black tips so I should be good.

I put the whole parts purchase thing on hold for a couple days as I had to deal with other stuff... Now, as I previously menitoned, I have to change the spark plug wires. I'm buying a new spark plug wire set off of Rockauto. (Standard motor products, if that matters.) I have to buy separate COP boots. Now I was wondering, is it one boot per spark plug? Or is it only for the plug on which the coil sits (Thus the COP acroynm?)

TL;DR: Do I buy 8 or 16 COP boots?
 

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Thanks for your help. I didn't know about the black tips! Anyway, the plugs I'm buying, according to the picture on Rockauto, do have the black tips so I should be good.

I put the whole parts purchase thing on hold for a couple days as I had to deal with other stuff... Now, as I previously menitoned, I have to change the spark plug wires. I'm buying a new spark plug wire set off of Rockauto. (Standard motor products, if that matters.) I have to buy separate COP boots. Now I was wondering, is it one boot per spark plug? Or is it only for the plug on which the coil sits (Thus the COP acroynm?)

TL;DR: Do I buy 8 or 16 COP boots?
If the spark plugs are the black tip, for sure you shouldn't have any problems. Most folks don't have problems with the silver tips either. I was just giving you a heads up on the potential problems and possibilities. Some auto parts places will try to sell you a mix of both. They just go to the part number and pull which ever ones they have. IMO, you're more likely to have a problem (misfire, rough idle, etc.) if you've installed a mix of the two types. That's why I use NGK copper core plugs in my 5.7's.....LZTR4A-11, Stock No. 5306......one part number and they're all the same, unlike the Champions.

Standard Motor Products has a pretty good reputation and their wires are normally very good. The wires should come with the boots on both ends.....one end plugs into a coil on one cylinder bank and the other end to a spark plug on the other bank. Make sure you don't mix them up on which goes to which. If you're not that familiar with the 05 Hemi's, it's easier to change one wire at a time rather than pull them all at once and then try to figure out what goes where.The coil over plug boots are the ones on the coils themselves. If someone, sometime prior, didn't follow the instructions in the Factory Service Manual and failed to put a small dab of dialectric compound on the boot where they plug into the spark plug, you could tear some or all of them when removing them from their respective spark plugs. Normally, if it was done correctly, there is usually no need for new COP boots. In your case, to be safe, you may want to order eight (8) of them and replace them all. They should only cost about $30 for all eight. The 2005 coils cover only one spark plug on each cylinder, hence the need for only eight. The 2006 and up coils cover both spark plugs (no more spark plug wires) on each cylinder and would need two (2) boots per COP coil.

To be clear on the 05, each cylinder has two spark plugs, one covered by a coil and the other covered by a wire coming from the opposite cylinder bank...the so called, Wasted Spark System. All boots, where they plug into the spark plugs should have a dab of dialectric compound on the ends of the boots so they'll be easy to remove next time. Because the spark plugs are metal and the cylinder heads are aluminum, only change them when the engine is cold. When installing the new plugs, use no anti-seize compound, check all spark plug gaps (.043-.044 in.) and TORQUE them all to 12-15 lb.ft. of torque. DO NOT over torque them. If you ever have to remove a spark plug and reinstall the same one, then you should use a small dab of anti-seize compound and again properly torque it.

Hope this helps
 
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