What could possibly cause the engine to seize up in my 98 Ford ranger v6? This happens without any warning from gauges or any noises or sounds from the engine it just completely shut off on me while driving and would not restart. I had someone try to jump me off several times which did not work I then had a new battery put in that did not work. No fuses blown, and I always make sure the oil is changed at the correct time and use good quality motor oil, and I religiously check all of my fluid levels under the hood for proper fill. I did have to replace the radiator a week or two before this happened because it had a crack in it and was losing coolant but I never let it completely run out of coolant..I would just notice that it had been leaking when I moved truck and would add more before driving and I checked it every single day until I could get the radiator fixed. When I took it to the shop they told me that the engine was completely seized up but I was just curious as to what would cause that when you have proper oil and coolant in engine? Thanks in advance for any answers!!

 

Welcome to the forum

Bummer about the engine, could be the Oil Pump or its drive failed, you would have seen the oil gauge on the dash drop to 0 just before the engine stopping
Never read about that happening on the Rangers 4.0l engines, 3.0ls yes, but not the 4.0l, but it could happen

I assume starter motor would no longer turn the engine over?

Engine can seize up from a few things
Hydro-lock, this means a fluid, like gasoline or coolant, leaked into a cylinder, and since the piston can not compress a Fluid it just stops dead in its tracks, this usually bends the pushrod or cracks the piston in that cylinder if engine was running and its a sudden stop of the engine, not a gradual loss of power
There would be a noticeable misfire prior to this

Spun Main bearing, if oil flow to a main bearing(crank bearing) is limited or blocked, the bearing starts to heat up and being a softer metal it melts and "spins" inside its journal which cuts off ALL oil flow to it, engine will start to lose power as the bearing binds up and once engine stops the metal will cool off fast and WELD the crank to the block so it can no longer turn

Spun Rod bearing, same can happen to a rod bearing if oil flow is cut off, although these can actually break the rod cap/journal and rod breaks and gets lodged between block and crank so crank can no longer turn, it can also break the block on the side and you can see part of the rod sticking out, if this happens it would be more like a hydro-lock with a sudden stop

The spun main or rod bearing would usually start to make a low KNOCKING noise just before failure
For hydro-lock there would be no warning, just a misfire