Went to a couple parts stores today to get the 3923 plugs but the part number 5224 came up for 97 and newer 5.9s (I have a 2000). Autolite doesnt have a 5223 so what is the difference between the 3924 and the 5224. I feel like I had this problem before the last time but I can't remember.

Thanks for the help

 

5224 is the stock regular Autolite copper plug for our trucks, IIRC. The parts stores' computers will tell you that 3923 is the wrong plug for our trucks, because its a heat range colder. Don't tell them your vehicle info, just tell them you need eight Autolite 3923 spark plugs, and they'll get them for you.

 

True, 3923s ARE NOT the correct plugs for our trucks. The 3923 crosses to a Champion RC11YC, which again is NOT the correct plug for our trucks. Similar, but not correct. This is why it is hit and miss with different people on our trucks. The correct plugs for our truck is a Champion RC12LC4. If you compare a RC12LC4 to a RC12YC (or a Autolite 3923) you will notice that they are NOT the same. This is my pet theory of why Autolite 3923s are such a hit and miss item with our trucks. Plus QC at Honeywell (Remember, they make Fram (Frap) filters!) is not that great IMO.

Since Champion doesnt make a colder version of the RC12LC4, you have to go to a different brand such as NGK. This is what I think happened when the person who came up with the 3923 idea failed. No Champion colder cross, No Autolite cross. So instead of going to another brand, they cheated and went to another plug design with a colder heat range.

My truck ran better on the stock Champion RC12LC4 spark plugs than it ever did on the Autolite 3923s. And it even runs better on a colder set of NGKs. The only thing I noticed with the 3923s was slightly better acceleration, but that came at the cost of longer cold starts and worse gas mileage.

The correct NGK cross is ZFR6-11F.

I know this wasnt the topic on hand, but I thought I should finnaly state my opinion on Autolite 3923 plugs.

 

I appreciate the info thanks. I wouldn't mind running the ngk's a step colder either, I like them... My question was though, how come the 97 and newer motors say they need a 5224 and not 3924? If i were to run stock heat range plugs would I have to run the 5224s and not the 3924s? This wouldn't be such a problem if autolite made a 5223, but there is no such plug.

Thanks, Jake

Edit: Sorry Jason I just re-read your post and saw that you have an 01, basically in less words, whats the difference between the 5224 listed for our motors and the 3924 listed for 97 and older?

The funny thing is I think im running the 3923s already hah

 

great info purpldodge!

 

The same reason I posted. The 3924 is a different style plug than the 5224. I believe Chrysler switched to the later to meet emission standards.

 

Dont get the Iridiums! Stay with what under the hood reccomends IMO...