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!!