Mechanical Morass

I ran into a peculiar problem with my 1991 Ford Ranger pickup a few weeks ago. For a while, it had been running poorly, and from a previous malfunction I had some idea as to why. There was likely a problem with a sparkplug.

A couple of years ago, I changed the plugs in this thing, and the truck ran great for a few weeks. After that, it started to sputter and lurch, like it wasn't running on all six cylinders. Checking over each plug, I found one of them had cracked. When I went to buy a replacement plug, the mechanic said it was the sort of thing that could happen upon installation, if you cranked them down too tightly. While that may be possible, I didn't believe that was the case for me, for the plug hadn't cracked until several weeks after installation. I just figured it was one funky plug, and left it at that.



That Sparkplug Sucks!

 Bringing us back to today; I checked the sparkplugs after the engine started sputtering, and again I found a busted plug. This time, it was more than a simple crack in the insulation. The whole end of the plug looks like it exploded! My camera really can't do this thing justice, but maybe you can see some of what the naked eye reveals about the insidious sparker.

I don't know why a spark plug would blow up like this inside an engine. I'm inclined to think there is something defective about these particular plugs, though they are ACDelco plugs, which are generally high quality. Regardless, it is clear that this particular sparkplug sucks!

There have been warning signs before a plug fails. The truck will start rough and begin to lose power going up hills. When I ask a mechanic about this problem, they generally tell me the thing needs valve seals. That may be the case, as this is an old engine, but I don't see how that would cause the sparkplugs to crack. It's a curious thing, indeed.