02 F150 5.4L V8 Triton Plug Problems

[Andrew1941]

I know this is the Windstar forumn, but you guys are so much more helpful. If anyone can give me insight, it would be appreciated.

A few years ago, I had the plugs changed out around 90,000 KM. Probably early, but I didn't know any better and thought I would do it as preventative maintenance. I paid someone to do it since it the plugs are so hard to get at. Well about 1.5 year after a plug blew out on the passenger side 3rd in from the front. Took it to someone else and he installed a heli-coil and a new plug, rest was OK, but it still cost $500. Then I asked him to check the rest and torque them all which he unbelievably charged me another $200 for. I stopped going to him after that. Now around a year later another plug blew, or at least I thought so. This time it is passenger side 1st from the front. I haven't done anything yet, but I did look down the hole with a flashlight and noticed the plug is still in the hole! I took a magnet and tried to see if the plug was loose, but it wasn't. I started looking around and found the individual coil for that cylinder is destroyed, a vacuum line is melted and found a rather larger (about 1" diameter) hole in the side of the manifold right beside where the coil was blown off the plug. Now what I am wondering is did the coil just let go and then it arced and blew the hole in the manifold or is the plug the cultprit or did the manifold explode somehow and take out the coil? I think I can replace all the parts myself and save a bunch of labour charges, but I would like to figure out what the heck happened so that I do not replace them and then have it happen again right away! Any help would be much appreciated.

The manifold looks similar to the one on the engine of an 01 Windstar. I never installed the Motorcraft plugs because at the time I didn't know any better, but do now. I was thinking about trying to see if I can unscrew the plug and if the threads are not damaged, I will just install a new plug and then replace the rest of the parts as required.

[Andrew1941]

Took the truck in to a mechanic and asked him to check what happened and call. He went ahead and attempted to fix then told me he fixed it, but i should get rid of it ASAP (charged me $550). It was a blown plug that the centre of the plug was melted and then blew out at the head and melted two holes in the head (one on each side of the plug). I guess he tried to machine down a new seat then installed an insert and new plug and coil. Regardless, it didn't work and it wasn't repaired. So far I got back 1/2 the money and trying for more. Better than nothing, but last time he touches one of my vehicles. The truck is being towed to an engine shop today and they are going to stick a camera down and do some investigation to see what can be done.

[12Ounce]

I wonder if your problems weren't caused by the replacement plugs being overtorqued and your cyl head being fractured. Many folks read the torque requirements for plugs ... which are usually offered in LB-INCHES and think they are reading LB-FEET.

The Windstar has a specified plug torque of 87 lb-ins (IIRC) .... that works out to 7-1/4 ft-lbs ... barely wrist-tight!