“The burning antifreeze vapor (essentially methane) is a pretty good theory here. What happened is she parked the car when it was hot and went inside.
That's when all the hot antifreeze leaked out and evaporated into the garage and into the automobile's interior. It was everywhere. Then, she came downstairs in the morning to go to the airport. Hopped in the car, put her key in the ignition (or maybe this had one of those chip controlled ignitions that starts up when your “key thing” gets in proximity. So it starts up. She puts it in reverse. As soon as that heating element in the catalytic device kicked up to 711 degrees (what, 20 seconds tops?) everything blew up. She would have been both burned and suffocated simultaneously, and probably knocked unconscious.”
Hmmmmmmmmmmm
They said the radiator was punctured.
I had not thought about the overnight aspect of this. The victim comes home a bit tipsy from celebrating the big merger. Runs into something in the front of the garage and punctures the radiator. She thinks, crap, I'll have it looked at tomorrow. It drips and pools all night with vapors being concentrated in the VERY SMALL one car garage and the water evaporating from the mixture. On the way out in the morning something (headlight? catalytic converter? other?) sets off the concentrated vapors.
If the video I posted a few posts up is real, perhaps it is plausible?
A bit more research indicates that while methanol was used in the early 1900s as an engine coolant, that practice was discontinued years ago because methanol is so volatile.
Reading the label on Prestone II e-glychol (yellow jug) confirms no methanol.