TDIDog

Buddys 1997 F150, 4.6L V8, 120,000 miles

Throwing P0304 code - Misfire on #4.

Pulled plugs and found that the top of the plug and up into the boot was wet with antifreeze (Or maybe Winter washer fluid - it hadn't evaporated off over night). Definite arc tracks along the insulator.

I have been trying to search here for information on if there is a common leak point on the intake manifold leaking coolant or anything else into this area and have come up short.

Was this likely a fluke and some water from some time got in there and sat long enough to eat the boot seal and provide a path for the spark? Or is there something common?

CatSkinner

Well, given the age, it could've always developed a leak, Id clean it up and see where things go.

__________________
Prius repellant, just add gas.

TDIDog

I guess what I'm hoping to learn is if there is a common fail point here, but maybe there isn't.

HEH...

Prius repellant, just add gas.

In the TDI world, it's "...just add diesel"

CatSkinner

I'm not sure there isn't, but looking at it from the age of the truck, it's difficult to claim a fail point. I diagnose things for a living, but I'm not an auto mechanic, that's just a hobby for me. I don't think I'd have the patience to do it for a living. When confronted with an anomaly on working system, getting the problem to repeat itself is one the first steps in trouble shooting. Hence, clean the fluid and see if it comes back.

Good luck!

__________________
Prius repellant, just add gas.

Bluegrass

Look up!
Heater connections above.
Anti freeze won't evaporate very fast if at all.
It's Ethylene Glycol.

TDIDog

Cleaning it and waiting, is a slow method and can work, but if damage is occurring because of waiting, I would rather know before the damage occurs.

If no one knows right off about a common fail point, then the clean and wait is the way to go.

And, BTW, I am a mechanic for a living. Just so you know. :)

TDIDog

D'oh! I had to fight around them to get to the plug. I'll have a good look at those hoses. Thanks for the smack in the head.

Bert

Besides the hose, check the fitting into the manifold.

__________________
Bert

TDIDog

Oh... I didn't see a a fitting back there. Is it one to/from the heater core? Eh. I have a resource that I can look at. Hopefully I can find some good pictures.

TDIDog

OK, I found a picture but apparently it takes time for pictures to happen here. But here is a try: