I can't seem to think that steel tanks baking in the sun all day long, combined with an engine in the back, would sustain a comfortable temperature for the crew, especially in fronts like North Africa. Did tanks during World War II have any sort of system to keep the tanks from becoming ovens for the crew?
Nope, the crews would just have to take it and ensure that they kept hydrated. The exception however is the M3 Stuart. It used an aircraft radial engine which was cooled by a big fan shown here. This sucked air through the vehicle and past its crew and was very appreciated.
Hatches. They had hatches. And yes, they were hot and miserable in the heat. A few had exhaust fans to pull fumes out of the turret, but that didn't help much. US tanks didn't get air conditioning until the M1A2 SEP a few years ago. The M60 series had hoses that were intended to force air into gas masks, but often got stuck into the gunner's nomex suit to cool him off.
The M18 Hellcat Tank Destroyer had the engine air intake in the crew compartment. This sucked in outside air through the open-topped turret. Great in the summer, horrible in the winter.
