What’s the skinny on 2000s Ford F150 ejecting/spitting out spark plugs? I found a great deal on a 2002 truck and then was scared off by research results concerning problem described above. Is this as widespread, expensive, and serious as it seems to be?
It was a problem on the 5.4L Non-PI (re: Pre-1999) mostly, but it still persisted in the later trucks to lesser extent. The good news is that if it was going to happen, it probably would’ve happened by now.
As I stated before the problem was mainly with the 5.4L engine, with the Non-PI engines being more effected, that the later PI engines. It has been known to happen in the 4.6L engine, but not nearly as much as it has been known to happen in the 5.4L. IIRC the 2001-up heads had more threads in the heads, and the issue of spark plug ejection was greatly reduced.
Just my opinion, but if the spark plugs are not overtightened (factory, dealer, independent, DIYer) then they should never blow out; shallow threads or no.
Many of those torque specs given for plugs are too high for a non-gasketed, tapered seat spark plug; especially for a shallow thread situation.
I’ve seen specs of 15 ft. lbs (give or take) and no way on Earth should a shallow threaded plug be run down this tight. Something is going to give and this means the threads will pull. Pulled threads will then lead to plugs blowing out or stripping at a future plug change.
A tapered seat plug in aluminum should be run down until it hits and then bumped snug. No more. A gasketed plug until it hits and then a 1/4 turn at most.
Thread repair can get expensive, true enough. The part I take issue with are the ones who claim the cylinder head(s) must be replaced when this happens.
When you make 10 million engines and 10,000 of them blow out a spark plug, that sounds like a big deal but it isn’t. It’s only .01%, one out of a thousand. Those are pretty good odds…
Ford now recommends aluminum inserts for repairs. They warn against steel ones, to preserve the heat transfer characteristics from the plug to the head. A lot of repairs have been done with steel inserts with no problems. Big Serts or Time Serts are recommended by many.