is it a common issue..Plugs blowing out?.. I have..

[yellow tang]

I have a excellent 2004 gt conv. 70k miles. now that I got top fixed ( line was leaking) I want to take 3 or 4 trips this summer to visit a friend. each trip will be about 250 miles or so total. no hard driving just interstate ( 70mph) and some in town driving. I heard the 4.6 was a great engine and is known to get high miliage. BUT ..I also read they blow plugs out of head? I'm almost afraid to take it on any trip. The tires are almost new..serpentine belt excellent..no lights on dash.. Am I pretty safe to go or is that plug blowout issue real common? Thanks

 

[Bronco2Fan]

I've had my 03 GT Convertible for 24 years/ 120k on it, and have never experienced that happen. But I have read the same thing before.

 

[BMS]

Unless you’re running boost, high compression, or racing it hard, just drive it. You’ll be fine.

 

[Mustang5L5]

Heads were revised in 2003 to feature more threads. The earlier heads only caught 4 threads. The 2003+ version now has 8-9 threads. It was more an issue on the 99-02 heads and common. Still happens on the later cars, but there are usually other factors in play (boost)

If your plugs have never been out, i wouldn't worry about it. The issue for the later cars is more for overtorqing when installed.

I have 70K on my '00 and no issues with the plugs popping out with the less threads. I replaced the plugs about 3 years ago (at 69K miles) and they came out and installed fine. I'm not losing sleep over it.

 

[SnakeBit!]

as long as they're installed at the proper torque settings, should be no issue.

 

[wmfateam]

I had one blow out of my 96 Cobra 4v when shifting at redline on track. But have never had that issue on any of my 4 GTs. Like mentioned earlier, the newer heads had more threads so not only is it a rare occasion, you are immune.

 

[96blak54]

2004 2valve heads were definitely 8thread sparkplug holes. Unless your car had plugs changed out and some dummy over torqued the new plugs beyond all comprehension, youll be A OK to drive the car worry free about spitting plugs