Spark Plug melted?????

[94Navahoe]

Ok so this is the thing, i just bought a 94 Navajo. Has a blown head gasket and Im in the middle of replacing it, and is going pretty well. BUT when i pulled the plugs out of the head, the plug in cylinder 3 was totally melted like the Eletrode thats in the middle was GONE and that little metal piece that arcs over it was melted back????? and in Cylinder 2 the eletrode part looks like it was blown out from the center and red?, with the metal arc melted away.... Now it looks like number 2 is where the water was going through cuz it was all white, and number 3 had slight water goin through..... But ive blown head gaskets before, runned turbo cars with tons of mods, but too much spark but have I never EVER seen plugs just straight up melt....
IDK if it matters they were Autolite(junk) Platium.... So wtf would cause that?

The guy had told me that the volts in dash gauge jumps around ALOT, like sitting at a red light it will dip really low then as soon as you start moving it would go right back up.... I was thinking loose belt even tho it didnt seem loose when I took the old one off.... IS this normal?

Thanks Guys for any help on this, and maby any other things that i might need to know down the road. I just replaced all the brake lines yesterday, and all the fuel lines. The truck had sat for well over a year and ive just been going over it to make it nice again... I guess u can say i just did a tune up too.. Im looking for a Exhaust for it, but rather build my own, so im looking for a set of exhaust headers that are nice down to the cat.... From cat back i already built my own set up....
ONE more thing lol..... the heater only works on high, and the fan sounds like there is a critter stuck in there, hard to get that out?

 

[Four0Sport]

i had a similar problem with the same cylinders. head gasket wasnt blown, wasnt loosing coolant. bent valves, destroyed my plugs, eventually burned the rings and filled the cylinders with oil. if youre replacing the head gaskets take the heads and have them checked. make sure youre not gonna have to go through taking them off again. hope this helps some.

 

[TeckNine4]

Damn,, the same thing happend to my boys 2.9-liter 88' Ranger STX, Blown head gasket and 2 of the plugs, the electrode was completley destroyed. I helped him with the process. When he bought it off the dude he said that he slipped a gear an over-revved it well into the red-line. These were Auto-Lite plugs also (I think there the best to run in Fords) and they had the white glazing on the rest of the 4...

 

[94Navahoe]

Yeah the head gaskets were skrewed, there back in, the valves looked ok... I really dont have the time to wait or the mone at the moment to get the heads checked, plus i was thinking it never overheated the time i had it and when i was playing with it a little, and steel heads are harder to have issues them alumium heads, its still smokin like hell but im thinking it would take a few hours to burn out all the freakin water... It took me 6 hours to do the job, and that includes all the "problems" i found along the way,like the oil filter didnt wanna come off lol. And exhaust didnt wanna come down. Not too bad i think for a first time.
Ima take it for a ride, grab some food, and run it up the highway and see wtf it does, and hold onto some water... I let it sit and run for like 30 minz, i dotn feel any water spraying out of the exhaust like before.
Well c LOL

 

[PDH]

Ok so this is the thing, i just bought a 94 Navajo. Has a blown head gasket and Im in the middle of replacing it, and is going pretty well. BUT when i pulled the plugs out of the head, the plug in cylinder 3 was totally melted like the Electrode that's in the middle was GONE and that little metal piece that arcs over it was melted back????? and in Cylinder 2 the electrode part looks like it was blown out from the center and red?, with the metal arc melted away.... Now it looks like number 2 is where the water was going through cuz it was all white, and number 3 had slight water goin through..... But ive blown head gaskets before, runned turbo cars with tons of mods, but too much spark but have I never EVER seen plugs just straight up melt....
IDK if it matters they were Autolite (junk) Platinum.... So wtf would cause that?

I know I'm late to reply, but I had the same thing happen with an Autolite Platinum Plug on my '94 Explorer on a newly rebuilt engine. The wire end that sits over the electrode entirely melted away. The plug got so hot the spark plug boot welded itself to the ceramic insulator on the spark plug. I replaced it with one of my original Motorcraft plugs.
Then about 1 year later, another Autolite Platinum plug went dead on the same vehicle. This time the ceramic insulator cracked. I blame it on the Autolite Platinum plugs. I'll never buy another Autolite Spark Plug in my life. I'm looking to replace all of them with some Motorcrafts right now. Which is why I read this Thread. Searching for 6 new spark plugs. Autolite Platinums aren't worth a $hit, IMO.

 

[PDH]

Autolite Platinum AP765 Melt-Down Photos

Here's two photos of the Autolite Spark Plug that melted down in my 1994 Explorer XLT. It's plug AP765. Stamped on the side of this plug is MADE IN U.S.A. - 08

A while after this plug melted down, another one of these plugs cracked the ceramic insulation from top to bottom, and that plug died also. I've ordered some Motorcraft AWSF42PP plugs and plan to toss the remaining 4 Autolites in the landfill - where they belong.

I wouldn't have dreamed this possible if I hadn't experienced it and seen it with my own two eyes.