1997 Montero 3.5L
The cause: Driving back from the store Sunday night and hear the valve train clattering. Defiantly NOT normal. Quick glance at the gauges shows ZERO oil pressure. Got it off the road and parked within 20-30 seconds of first noticing the noise. Growing puddle of oil under the front of the engine. After the tow home I got into it a bit. Pulled the skid plates off and found the oil filter sitting on them. Yes, it backed off and eventually fell off, dropping pressure to 0.
The next day: After replacing the oil filter and a careful cranking (ignition disconnected) to build oil pressure it started on the first turn after I hooked up the ignition system. Noisy but full power available, no smoke out the tail pipe. A short slow drive later the engine quieted down but oil pressure is low. Drove it a bit more and oil pressure dropped as things warmed up. Cold start shows 2.5 BAR on the gauge, when warm it shows slightly less than 1 BAR.
The current status: The top end sounds still sounds good. Not blowing oil out the tailpipe, not pressurizing the crankcase (rings still good?), valves still seem to be acting properly. The bottom end not so much. Sounds like rocks rolling around in the crankcase when its under a load. At idle it doesn't make noise at all.
The question: First, can I pull the oil pan off with the engine in the truck? Second, if the journals look good can I get away with replacing the bearings? Will tools, Plastigauge, good calipers and common sense get me through this or is a full rebuild needed?
