I recently bought a 1997 Ford Econoline 150 with the 5.4L triton 2 valve SOHC v8 53,000 original miles. It is a conversion van with the fold down bed bench in the back ha ha ha 😂.
Sparkplugs are a known issue in this and the DOHC 3 valve redesign of it. The issue in my engine is that eventually it would blow a sparkplug out and through the hood! This because there are only 3 threads keeping them in. Question is should I get the plugs replaced because of their age and milage? The van runs and starts fine. I'm thinking if they are working well leave them alone i wouldn't want a mechanic to cross thread a plug and ruin 1 of the 3 threds just to change plugs that are working fine now.
P.S.
I bought this to replace my 2013 Outback for several reasons one being the CVT transmission in the Subaru. I figured that even though the Ford is 16 years older the cost to maintain it would be less especially if I had trouble with that CVT.
P.S.S.
I'm changing all the fluids in the van and adding a little AT 205 reseal to everything (except breaks). No problems now but I figure a tablespoon with every oil change and a few tablespoons in the transmission fluid and power steering fluid is that preverbial ounce of prevention.
I would pull one out and inspect it to see the condition.
If I were you I would find a mechanic who has extensive experience removing plugs on those particular engines - it is not trivial and you can do more harm than good removing them (in the hands of an inexperienced mechanic or DIYer). It won’t be cheap either but you would have some piece of mind afterwards.
https://repairpal.com/tsb-for-possible-ejection-of-spark-plug-from-cylinder-head-518/problems/page/2
What did Ford botch so badly in that engine that simply removing spark plugs can mess something up? I've heard those 5.4L V8s had issues long before Scotty's page and channel but never knew specifics.
They have been known to actually spit out spark plugs while the engine is running. Not enough threads in the head to hold the plugs in securely. Very poor design. (To use one of their old slogans from the 1960s, "Another better idea from Ford!"
@justin-shepherd the threads on those 2V engines were short and soft and easy to strip if not careful, also why they eject out. There was a TSB for stripped/missing threads:
https://www.tsbsearch.com/Ford/07-21-2
That sounds like somebody was either in a hurry or didn't fully use their heads when they designed it. I'm guessing the heads are aluminum, and the steel threads on typical spark plugs easily strip out the aluminum? Sounds like if the loosening of those two plugs in my Catalina happened in that 5.4L it could've been a disaster.
Might as well do it now rather than waiting for them to stop working.
I'd have an experienced mechanic swap them out for peace of mind.
