I sold my 93 Explorer with the 4.0 at about 205K, I was running Mobil 1 5-30 winters and 10-30 summers mostly, it would burn about a quart every 4 or 5 thousand miles. Oil changes were anywhere from about 8 to 12,000 miles. I kind of kept increasing them the older the car got, figuring what's the point as I would be soon riding a rust eaten wreck with a nice engine. But when I sold it the engine was not much different than when I bought it, except a bit more ticking from I think the rollers. Never had any engine related problems but did get noise for a couple of minutes during winter start ups. However, it always cranked immediately with just one turn of the key even at -15. Not the slightest bit of leakage from gaskets, in fact the engine outside was completely dry and rusty no sign that anyone had put oil in it ever.