How to you store the random oil jugs?

[Ortimber]

Your Tacos run 0-20 though right?

No, the V6 engines spec 5-30.

 

[Gary Fowler]

Any details as to why he thought the oil caused the failure?

If engine blew, likely it was because it didn't have any oil in it.
15W-40 should work in any engine except in below freezing conditions and even then is should not "blow" an engine. It might cause some pre-mature wear at start up and make the engine a bit hard to turn over but nothing else.

 

[Jstpssng]

Has anyone had a problem with anything by using the wrong oil?

I did, with my '84 F150 which was the last new truck that I bought. I changed the oil religiously using Quaker State 10-30; by the time it turned 50K miles it sounded like a sewing machine going down the road. One day a lifter collapsed and it started knocking so hard that I pulled over, and made arrangements to have it towed home; after talking to my father I let it set a couple of hours and it sounded better so I drove it home.
I did some reading and found that QS is a paraffin based oil and was known to coat hydraulic lifters. I changed oil brands, dumped some Marvel Mystery oil in it, and ran it; over time the engine quieted down until one day I was in hilly country so I dropped it into 3rd and ran it hard to get the rest of the crud out of it. I put another 120K miles on it before selling the truck.