jaiello

I have to do the dreaded spark plug change on my 2006 f150 lariat 5.4l. I cant seem to find a straight answer. Has ford redesigned these plugs from the two piece to a one piece? if so what is their new redesigned plug parts number. I only want to use motorcraft plugs I know about champions one piece blah blah blah but I heard nothing but nightmare stories on those. misfires, etc.. if anyone knows the please post thanks.

SCORGE

New part number is SP-546

jaiello

Thank you

nrivera04

They are still 2 piece design, but the crimp/weld (whatever you wanna call it) appears to have been of better quality resulting in less breaks. I don’t think I’ve seen anybody have a break with an SP515/546

redfishtd

orig plugs sp 507 prone to break off due to two piece design and carbon seizing tip . Cost many owners thousands to fix -- class action lawsuit . Your lucky to get a check for thirty bucks.
sp 515 welded tip on but tended to be bad about failing right out of box due to manufacturing problems of weld area .
Sp 546 tip totally redesigned not even announced just started showing up .
None of these plugs are double platinum
Champion 7989 are double platinum and I have run three sets to avoid these mc errors . I have had no problems no failures . I change them before 60k . One set changed early because of timing job .
I have a box of 515's that I'm going to give away - I almost drank the cool aid .
So who is making reliable plugs ????

FrozenTundraGuy

My MC SP 515 were replaced @ 50K, and everything went smoothly, but I did notice they were quite worn for the mileage-wouldn't have lasted to 70K at best. I plan to replace with the latest MC plug in a few yesrs-whatever that number is.

techrep

iTrader: (1)

Ford recommended plug change for 04-10 5.4 3v is 60 k miles now.