I learned a way to keep car interior cooler
 

As some know, I went beyond tinkering with a 20 year old subaru and the worlds most efficent four cylinder design, by welding, actually adding weight, adding aluminum, and steel where necessary...and worked fuel back up into high 30s even wtih snow treads on (rally type tire- it is a subaru).
An epiphany upon undercoating a simple two inch wide strip of rocker panel...approx 6 feet on my wagon..
I turn the vent blower on cool and it was actually cool on a hot day. It has always been warm.Thought nothing of it, until it did it again after sitting all day in hot humid sun.
Underside creates the interior temp? I thought since then of a few other unibody channels that I will treat, even tho the factory did not treat it, worth a mention. Alot of cheapskate in auto manufacturing. I am glad to doubt it all, one thing at a time, even unplanned findings. this was just another one.
I also noted that .25 inch foam panel will fit under the rather solid roof liner, even though I have not felt warmth from there, it only shows that the cool inner body channel's go to the roof as well, one large sneaky hidden system, and it is for more than acoustics, but thermal comfort.

No way - really?

Where do you think might be good places to add insulation in my truck? It's never had air, so anything that could reduce the interior temp can't be a bad thing.

I even tried piling ice onto the cowl vent once; no effect.

I know there is a big difference cabin temperature if you insulate the floor pan on a Jeep. What material did you use?

Or you could go to Roshgo Corporation
they have a plug in fan that goes in place of a Igloo 25 qt or Coleman 28 qt cooler lid. It draws air in from one end....over the ice.....the blows it out the other end at about 50 degrees. I ordered one for my Geo and will take it to the race track to put in my car between runs!

a swamp cooler?