Driving my 1998 3.0 2wd auto ranger (180,000mi) , I was about a mile from my exit on the freeway when I noticed that something under the hood was ticking. It quickly got much louder at which point I noticed my oil pressure was bottomed out. I started losing power then right as I reached the offramp, the engine stopped running so I just rolled onto the shoulder to check it out. I didn't see anything wrong under the hood and my oil level is still just fine so i tried starting it, but all I got was a click. This is a 4 month old starter and I couldn't believe it was bad so j unbolted it and turned it over to make sure. Sure enough it kicks out and spins. So I am kind of totally at a loss as far as what I should look into next, but a couple of people from work have told me that it is probably seized up and ruined.

So my questions are:
1 what is the best way to turn the engine over by hand to ensure that it is not actually seized?
2 what is the most likely cause of this incident? Oil pump? Clogged oil pickup screen? Or I keep reading about a camshaft synchronizer shaft or gear or something that these are notorious for having fail around this late in the trucks life...

Any and all help would be greatly appreciated. the truck is stuck at my work until I figure out what needs to be done or if its reached the end of its run, so your promptness is also appreciated..

Thanks guys.

 

You can use a socket on the crank pulley bolt to manually turn the engine

From description it does read like an engine main bearing got overheated and spun in its journal, which causes engine to lockup/freeze
Oil pressure is used to cool the bearings, not just lube them, so when you lose oil pressure it only takes maybe 20 seconds for main bearing to overheat, like if the fan belt broke and water pump stopped working while driving, engine overheats pretty darn quick

As to the cause for loss of oil pressure, the cam synchro is the oil pump drive but it usually doesn't fail in this manner, it will make a squealing noise when upper bushing wears out, but thats about it
It is possible its cam gear stripped, again possible but not common
Pretty much every V6 or V8 engine uses the same oil pump drive setup as the 3.0l, used to be distributor there now its a cam sensor, but exactly the same below that to oil pump drive

Oil pump pressure relief valve may have failed, or the pump itself
Oil filter may have failed

Anyway, first find out if engine will spin, remove spark plugs to make it easier to spin, i.e. no compression
Engines spin easily with no spark plugs