S**t motors

[EX-excursion]

I know what the tech bulletin says.....but in a vehicle like the one the OP posted about that has this SERIOUS issue of shooting plugs out.... you want to do exactly as I said. Curious note.......Two local Ford dealers I know of pull and install plugs on 5.4's like the OP's; with the engine warm.

As far as the spark plug material expanding too.......it's not a factor. Coefficient of expansion Aluminum (head mat.) expands at twice the rate of the plug.

Factory conditions on a new, un-run engine are completely different that an engine that has 70k+ on it.

 

[rjdelp7]

I had my plugs replaced at the dealer($100, well worth it). They had me drop it off the night prior. They explained, they pull it in the night before and work on them, cold in the morning. There were to many issues, before Ford, figured this out.

 

[EX-excursion]

I think perhaps some of us are talking about engines of certain years that had more problems & are a little more than 'well worn'........ vs. newer 5.4's that didn't have those problems to that degree. Might explain the differences.

 

[FisherPete]

I think perhaps some of us are talking about engines of certain years that had more problems & are a little more than 'well worn'........ vs. newer 5.4's that didn't have those problems to that degree. Might explain the differences.

Indeed, the newer 3 valve version also has much deeper threading on the plugs ... if I were to replace the motor in a '99 because of concern over the plugs, I'd look for a newer Triton.

 

[EX-excursion]

FisherPete....... EXACTLY. The newer 5.4's are different animals from the early. I own the newer 5.4 and I wouldn't own the early version just as you stated.