Looking at a 2003 ford f 150 with the 5.4. I've had a few people warn me about these engines and the spark plugs. What's the deal?

 

people fail to properly torque the spark plugs, and it results in the plug ejecting from the head and destroying the COP...



sometimes it takes a thread or two of teh head with it, a lock-n-stitch insert can solve the issue and keep the truck good as new

 

The "earlier" modular motors had but three threads in the head to engage the spark plug body, this was thought to be the main cause of blown out plugs. IMHO improper plug installation was probably more at fault than the design. While its a much discussed issue here at times and can be considered somewhat common or not unexpected its true incidence of occurrence isn't so widespread we'd say "all modular motors with early heads definitely have this problem.!"

There are indeed a few very good repair procedures, DIY is possible but most better shops would charge about $400 for just one hole--not sure what they do if its more than one (a uncommon situation at one time.) Time-sert is the most frequently mentioned system here on FTE.

Not only is proper installation important removing plugs left in too long (more than 50K miles typically) is vitally important too. Such plugs can all be changed in one setting but if its known they've gone 100K miles or more its best to set aside at least two days. Anticipating use of a penetrating fluid like PB Blaster or Kroil, letting it work naturally takes a bit of time.

Too late to be short but both the V10 and V8 modular motors are great designs---I'm running one with 272K miles, another with 175K miles, trouble free apart from regular maintenance and upkeep.

HTH

 

I'd agree with JWA on the plug issues, not that big of a problem, changing them out is another story. Requires considerable patience on the 2 and 3 valve modulars in super duty clothing. My 01 F250 sb, SC, xlt, auto, 5.4 2V, has 262K on the clock and very few problems with it. Have heli-coiled two plugs in it, one on each bank and no worries. Solid,solid Motor. My 05 F250 LB,SC, auto, 5.4 has the three valve configuration and its a bit more complicated; VC timing, Cam phasers, VCT solonoids, Not sure when Ford changed to the 3 valve motor but haven't been as happy with it. Truth be known if they have been well maintained; fluids and filters every three thousand miles they should last well into the 250-260K mile range. Good luck.