How does the engine cooling system on a Hummer work?

Question

I am wondering how the cooling system on a Hummer works.. I have seen it briefly and the engine seems back and inside the body of the hummer and the radiators are where the engine is normally on a truck and they are angled.. and have an opening above the radiators.. does this help cooling significantly? Do they use electric fans to cool the radiators? Or an engine driven fan?

If anyone knows where there are some good diagrams of the internals of the hummer that would be great too..

I'm talking about the original general production models.. not the pure military or the H2 or H3 etc.

Answer 1

Because the Duramax engine has cooled Exhaust Gas Recirculation and an internal engine oil cooler, the team had to deal with a big 40% heat rejection increase to engine coolant but were unable to increase the size of the cooling pack between the air-lift brackets that protrude from the hood. This meant dramtically re-engineering the fan system, putting the fan directly under the coolpack and driving it through a new special gearbox, directly off the crankshaft damper pulley. Several other cooling system modifications were required to assist with cold-starting from minus 30 fahrenheit.