Driving through Knoxville last night. Loud popping under hood. Stopped popped hood felt leak from passenger side coil pack #3 I think. Coil is still intact and secured. I've heard of the plugs ejecting from the aluminum heads. But my plug is still in the cylinder. Could it just be loose? Maybe threads are still in tact? 500 miles from home. Should I have it towed to shop to try to not damage threads any more? I was only going about 10 mph when it blew. And pulled into a hotel right away? Any idea of repair costs best and worst case scenarios. Thanks guys

 

First thing is to find out if it back out or if threads are stripped. Take off the COP and try to thread plug back in. If it secures, torque it to 28 ft lbs. if it does not thread in, get a Timesert repair kit.

 

Blown out plugs were only a real issue on 1997 - 2001 trucks as I recall where they had just 3 threads holding them in. It didn't take much to over torque them and damage the threads - leading to a blow out. So that would mean your truck has the redesigned heads with more threads holding the plugs in place. This would also make blowing a plug out pretty unusual. Have the plugs been changed recently by any chance?

Getting back to the problem at hand, without looking down the plug bore to see what's still there - and looking down into the cylinder bore with a borescope to see what's going on inside - it's tough to say how much damage you've got. One thing I can say is that if anything got down into the cylinder bore itself, the damage happens almost instantly. Even pulling off and shutting down as fast as you did wouldn't help if something got down in there.

Let's hope for the best scenario where something (maybe the porcelain) blew out and all you have is a busted plug and a compression leak due to what's missing. That would be much easier and cheaper to fix.

 

Yeah hopefully its a busted plug and not stripped threads. Working on it myself is out. Nowhere near my garage and tools. Ford dealership is about 2 miles away. Would driving it be a bad idea? Pay for a tow?

 

Generally speaking, yes, driving it would be a bad idea. But as I said, if anything went down and in instead of up and out, the damage is most likely already done. And without looking down into the cylinder, it's hard for me to tell you what happened or what to do.

Let's just hope you blew out the porcelain and all it takes is pulling what's left of the old plug out and threading a new one in. Make sure to check the threads very carefully.

 

Shop called... Blown out plug stripped threads and bad intake gasket. Shop wants to put helicoil in. So far quoted $950 for all plug change, cylinder thread repair, new intake manifold gasket and new coil boots

 

Well, on the plus side, it doesn't sound like any internal damage was done. On the other hand, that's a pretty decent chunk of change. Sounds a bit steep, but you're not exactly in a bargaining position right now.

As for a Helicoil, they actually work pretty well when installed correctly. Did somebody change the plugs recently? Just wondering about the root cause.

 

Bought the truck from ford dealer with 65000 miles has 115k now. I haven't changed them. Probably original. Shop said 2 other plugs were loose. Back on the road now. Truck is running good so far. My gas mileage seems a little worse but I'm running mountains