Two good things in 24 hours? Improbable

So, I got the radiator for my truck yesterday. I installed it this evening, put coolant in, started up the truck.

A visible amount of steam was coming from the tailpipe. White "smoke" from the exhaust means a blown headgasket with coolant getting into a cylinder.

Was this steam evidence of a coolant leak into a cylinder? Well, many new cars have very efficient catalytic converters and one of the products of running exhaust through a catalytic converter is water. That's why you see water dripping from the tailpipe of the person in front of you in a traffic jam. So, this could have just been the expected water condensing more quickly due to the fact that it was ~35F outside.

So, I put a piece of cardboard under the tail pipe, and revved the engine a few times. If there's a leak from the cooling system into the cylinders, this would cause more coolant, possibly some red coolant to come out. All that seemed to come out was water and some carbon, which could have come from the exhaust pipe.

So, I took the truck for a drive. It should overheat if the coolant is being sucked through the cylinders; eventually there wouldn't be any coolant.

I first drove for about a mile or so. No ill effects were obvious.
I got home, shut off the engine and tried to start it again. It started right up. It should have trouble starting if there's a leak for various reasons:
1) No/low compression in one cylinder. This would cause that cylinder not to "fire" correctly. This was not happening.
2) Wet spark plugs. If the spark plugs have water on them, they won't spark correctly. This was not happening.

I checked the oil dipstick for water. There was none.

I need to do some more testing, but it seems like the $15,000 engine suffered no terribly ill effects from being driven more than 10 miles with no coolant (none! Yes, I knew it was stupid, but impatience and frustration often gets the better of my intelligence). I cannot believe this. It's crazy.

Here's the thing that makes it almost believable.

I once almost (by all rights, should have) destroyed another Toyota engine.
I drove my 1989 Toyota pickup from Tucson to Flagstaff to my dad's ranch, ~60 miles east of Flag. Either on the way to my dad's place, over a rough, rocky road, or on the way out from his place, a rock punctured the oil filter. The oil escaped during the trip to Tucson, ~285 miles away. Over the next two weeks or so, I drove the truck around town. There was no oil in my driveway in Tucson; this loss of oil did not occur in Tucson.

Since the truck needed an oil change and I didn't have the time, I made an appointment with a local shop, about two weeks after going to my dad's ranch. On the way to the shop for the oil change, I noticed that the oil pressure was at 0 and the truck hadn't been responding very well. I stopped at the store and put a couple quarts of oil in the engine. When I got to the shop, oil was pouring all over the ground.

This engine had been running on the fumes of synthetic oil for about two weeks. It ran fine afterward.

If my Tacoma really survived this, I believe I have no reason to ever buy a non-Toyota vehicle.
Crazy.