Is there any way to prevent a plug blowing or is it just by chance? Would putting new plugs in decrease the chances?

 

I think you have other problems if you're blowing plugs...

 

Actually no, these modular motors 97-03 are prone to blowing plugs out of the head due to a lack of threads in the head.

davisenvy,

I would check the plugs twice a year or so just to make sure that one or two haven't loosened themselves. Other than that, it's basically cross your fingers that one doesn't fly...

 

I'm new to this board but after reading all the posts discussing this subject i'm of the opinion that the plugs that blow out were improperly installed and were over tightened and stripped when they were replaced. These plugs are left in place and gradually over time work themselves loose and eventually blow out. I hope that none of the plugs that were originally installed at the ford factory have blown out. There are 100s of 1000s of these motors in use today and I think it would be a much bigger problem if it were a factory defect.....I don't know...just my 2 cents....sd

 

Actually it is a huge problem if you are one of the the many people who have had one or more blow. It's fairly obvious to most observers that there was a problem with not enough threads in the heads for several years. Carefully torquing the plugs to spec seems to reduce the problem, but there are far far too many posts from people who just got unlucky even when their plugs seemed appropriately well torqued. It does seem to happen more often with the 5.4L than with the 4.6L though.

I'd just suggest that you might want to hang on to that 2 cents until you research this problem a little more. There are a lot of us who know darn well that our plugs were torqued correctly. There are hundreds of posts at a minimum on this problem....and lots on the F-150 forum too....

And to rattosh51, since you have been around the forum for a while, I have to respectfully disagree with you. I'm sure you already know that there are a lot of other owners who will also disagree. They and I believe that the threads were a distinct problem for several years (thankfully not any more). One of the reasons people were really upset was that Ford took so long to fix the problem.

But, at least the timesert and keenserts people have done a fabulous business with the repair kits.

 

This is why this is a great forum....learning every day! I had not heard of the blowing spark plug problem before, or I had just not read about it here. I've only changed my plugs once since I've owned my Expy, and I had a shop do it. Great, another thing to worry about. Glad there is a fix-it kit out there. Lack of threads makes this obvious as
to what is going on. Thanks for the education....again.

 

Scottspoerry, was your blown plug/plugs the original plugs from the factory?

 

nope....replacements, but I checked the torque cause I had heard about the problem.

No, but I wonder now if the threads got damaged on the first set and just didn't have a chance to blow before I replaced them.

 

For those of you that have changed the plugs your self was there much if any antiseez on the threads. If there wasn't this could be part of the problem. The antiseez helps to keep the aluminum head from reacting with the steel plug. If there isn't much on there galvanic action could be corroding the threads and since there isn't much in the way of threads to begin with, they blow out.

Matt

 

Isn't this process also called electrolysis? This happened to the slide out on my camper. You can't mix aluminum and steel. If this is the case, couldn't this be considered a manufacturers design defect. Ford should know better than that.

 

Like I have posted before, all of the modular motors since 1992 have had the same design and haven't had a problem with popping plugs. The problem with the trucks lies in the tuning. The trucks try to stay in closed loop for too long when going WOT which causes the truck to be too lean and the cylinder pressures shoot up causing the plug to blow out. If you look at the spark plug that blows out, you will see that the gap is closed. This explains it.

 

Above from Consumer Affairs.com. The cars blow plugs too.

Below is a link with many owners who have blown plugs. Be sure to have plenty of time on your hands when you start reading.

http://www.consumeraffairs.com/autom...ord_spark.html

 

Steel plugs in a aluminum head is not bad as my vette is an 86 and it has aluminum heads, but I made sure to use antiseez on them and the ones that came out had it on them also, but most likly were not original. Just wondering if the factory plugs had it on them. I have 60,000 miles on my 99 and wonder if it is some thing to worry about.

 

Import cars have had aluminum heads for 40 years.

 

So your stating here that the plug will only blow out if the go pedal is put thru the floor boards?

Your logic may be correct, but if the head had suffecient threads, the plug would stay put under these cylinder pressures.