I have a 2003 Expedition with the 5.4L and am curious when Ford fixed the dreadful spark plug blow-out problem. I have heard the heads were bad all the way through 2003 and some 2004. Then I hear this is not true and the heads were redone after Oct 2002 so if your heads have a date of Oct 2002 or later you are fine. I have read thread after thread after thread with regard to this and no one, not one person has a definite answer. It seems so many people out there know someone who works for Ford and all of them have a different answer.

I just changed my plugs last Saturday at 69K and they needed it. I was surprised Ford says 100K as mine would have been about worn out by then. I would say 70-75K is the limit. I used the OEM plugs for replacements. It was a real PITA getting the back plugs out but overall not impossible. Some people said you need to remove the fuel rails but you don't. Or at least I didn't. My plugs were in there good and tight and it felt like the threads were coming out with them when I removed them. The threads on the old plugs looked fine though. I used plenty of anti-seize on the new plugs and they seemed to thread in nice and easy.

I looked on the side of my engine (drivers side) and there is a sticker on the lower valve cover that has some numbers on it and says 5.4L and a manufactured date of 12/03/03. So it looks like my engine is a late 2003 engine. I hope it has the newer heads.

 

'03s got 8 thread heads but there are still stories of them blowing out of even '03 heads but you have to believe the chances are reduced quite a bit with double the threads. That said it still all comes back to proper torque and proper change intervals, not the rediculous 100K Ford recommends.

 

Thanks for your reply. On the torque issue, I just snugged them a bit and then 1/4 turn. They felt pretty tight. It felt about the same effort as removing them. I know I know should have torqued them but I was afraid with the 1/2" torque wrench I had (only one I had and all the auto store had in stock). I don't think I could have got the the back ones with this.

I agree with the change interval. 100K is too long if you ask me. I almost went with Iridium but opted for OEM. Glad I did, I feel more secure with what Ford recommends. I think if Iridium was so great Ford probably would have used them considering what a PITA it is to change the plugs on their engines.

 

Another thing, I was reading that the heads were redone in Nov of 2002. I think I said October. I heard they used up the old heads on the the 2003 until they were all gone and then began using the revised heads. So you could have a 2003 5.4L with the older heads if it was manufactured in late 2002 and and early 2003.

Considering my heads say 12/03/03, which is over a year later, I would have to say my heads are probably the revised version. I hope they are. Pisses me off Ford wouldn't stand behind this and do a recall. I like Fords and I like to support American products and workers but next time I shop for another vehicle I may pass on a Ford. At least if I buy one I will investigate the model and problems first. When I bought my Expedition (used at 26K one owner) I had no idea this problem existed. If I would have known, I would have never bought it. It wasn't until like 3 months later I was treating a mechanic and we were talking about trucks; I told him what I had and he said "did you know those blow the spark plugs out the heads?" I was like WTF did you say? I researched it and couldn't believe it. He also said not to wait until 100K to change them, said that they have changed a few around that mileage and the threads came out with the plugs. He said 70-75K tops.

 

Small percentage compared to the millions out on the road!!!

 

My 03 did NOT have the new upgraded heads with 8 threads!

 

Phil, look on the drivers side lower valve cover, I'm curious what the manufacture date is on the engine. Like I was saying, it possible your 03 was built in 2002 or early 2003.

 

Ive got a 02 F250 sd 5.4 with 81k It just spit its second plug in a month. Trying to figure what to do next, probably changing the heads grrr not what I had in mind for those funds

 

Sorry,,,the stock valve covers are long gone,,lol.
I'm pretty sure it was built in late 02 to early 03