Hey all… I tend to be more a reader vice a poster and I have been doing a lot of reading about spark plugs as of late. Seeing as how I just bought this (used high mileage) truck I plan on doing routine maintenance so I have a baseline going forward. I got the Haynes repair manual and went to the spark plug section. In that section it stated up front the TSB that is for 04-08 F150 (broken plugs) and that I should not perform this service. But after going down numerous rabbit holes I concluded that I have no idea why this was even mentioned in this repair manual (1997-2003).

Anyways, I had no idea about the blown spark plug issue until I went down these rabbit holes and now I have some questions that after numerous hours of digging I can’t seem to find the answers to. Hopefully some of you all can provide answers to them.

1. Is there a way I can tell if this truck has ever experienced the blown plug problem? If not and if it has experienced this problem, I assume I can still torque to the suggest 28 ft/lbs for the spark plugs.

2. On the blown out spark plug website under FAQ’s, number 49 states “In late 2003 the SOHC 2 valve type engines were upgraded to a 8-10 thread spark plug design.” I do not doubt what is being stated; however, I can’t find anything outside this website that confirms stated clam. If this is true, what month/year did this production change occur and where can I find the source?


If answers to these questions are already out there, I apologize upfront for creating a duplicate thread.

Thanks in advance for the assistance!

R,
Chris

2003 5.4L King Ranch 4x4

 

chris,

as to #1....
if it has been done correctly it should be very hard to tell if there has been a "insert" in there to correct a past issue. other wise, one could maybe see a slight ring around the threads. Probably more noticeable on the piston side of the head.

as to #2 ...
I thought it was later in 03' that the "thicker threads" came down the line.
but I can't locate confirming info....perhaps a call to a the dealership could clear it up. If you're try to see if your truck has been equipt with the thicker threads....you will prolly need you vin # and build date.

or, but still not definitive note post # 22 in the following link >>>
https://www.f150online.com/forums/19...percrew-2.html

 

Enriched,
Thanks for the reply. Based on what you wrote for number one, leads me to believe if there was no issue (yet) and/or if it was repaired correctly a torque of 28 ft/lbs will not cause any issues.

I will check my build date tonight and I may give the dealer a call.

Thanks again for the reply.

 

It's not the build date that determines how many threads - it's the head casting numbers. The dealer won't be able to help you. ASSUME you have the 4 thread heads and treat it accordingly. Very few 2003 trucks have the 8 thread heads, and even a few early 2004 4.6's have 4 thread heads.

 

Thanks for the reply. After reading much of the 27 pages of living with the a blown plug, that is pretty much what I figured.

What I find funny, is that by changing my plugs (which I am going to do) I may very well be opening Pandora’s Box but not really.

 

Motorcraft plugs, no antiseize, 28 ft/lb, you will be fine.