Hi All,
My 01 Ranger 4.0 SOHC has been out of commission since late July this year and I haven't been able to really work on it, but I'm about to head off to college and need to get it running again. I had another thread a few months back titled "Dirty Fuel?" where I talked about my ranger that had just suddenly started to run rough and sounded like it was barely running on half of the cylinders. I thought it could possibly be dirty fuel and clogged injectors since I had fueled up and drove down the street to work, then my symptoms started the second I fired it back up once I got off work so I had it towed home. Since then, the motor has locked up and that's when I gave up. I've been thinking about possible causes since I haven't been able to tear into it yet but I've been thinking of a broken timing chain since I had the loose/faulty chain guides that rattled on startup. Now that I'm thinking more about it, when I first started it after work there was a loud whirring noise and there are videos on my other thread of it starting up and the oil pressure gauge dropping a few seconds after. Now I'm thinking my oil pump possibly went bad and spun a rod bearing causing the engine to seize. I'm just looking for opinions on what could've possibly happened so that I know where to look when I tear into it. Thank You!

Here is the video of the startup after the symptoms started, but before it seized:

 

Plan on pulling and rebuilding, or replacing, the engine

Spun Rod bearing won't seize an engine, only spun main bearing, or something blocking piston movement

Have you tried turning crank using the crank pulley bolt, and tried to turn it in BOTH directions
If it turns a little one way but not the other way past a certain point then a valve is stuck open and hitting the piston
This could also be why no oil pressure, oil pump is driven by "jack shaft" which would stop turning if timing chains failed

In any case it can't be repair in vehicle, the engine will need to come out for further diagnoses

check https://www.car-part.com/ for replacement engine
2001 to 2011 Ranger or Mazda B-series 4.0l SOHC will work, you may need to swap over intake parts to match 2001 wiring depending on which year replacement engine came from

 

Personally, I would suggest a rebuilt long block by a reputable builder with good rating and guarantee. I have been dealing with a 2010 4.0 since April and have just gotten it running. Pulled engine 3 times, first to replace, 2nd because of bad rebuild job, can cap bolts stripped (not done by me) , third was suspect of bad timing done on head replacement done by me. Wasn't the case. Since I have dealt with crank/cam sensors. Have .090 clearance in crank sensor, drilled holes on mounting holes way oversize to be able to advance or retard timing. Finally running after retarding as much as possible with .090 clearance on crank position sensor. Puzzling to me right now is the engine oscillates at 3K rpm sitting still but took it out for a drive and went to 5,500 rpm without a miss fire. My rear timing cassette went out at 178K, yours appears to be 183K. Buy a lot of tools, believe me, you'll need them. Good luck.