This is going to probably sound like a dumb question, but since I do not work on buses, here goes. On Amtran and IC RE's with the radiator at the rear of the bus, does the air flow outward (from the engine compartment) or inward (from the outside)? What got me curious is the lack of any kind of air scoop from the outside.
The air flows inward through the air intakes on either side of the bus. If you look at them, you'll see they have a piece that flares outward to help pull the air in.
I didn't realize there were air intakes on the sides. I thought that the big grille at the rear of the bus was the only place for any air flow. I'll have to take a closer look nest time I see one of Longview's 2003 model IC RE's. It made more sense to me to draw air from the outside, but with the grille at the BACK of the bus I didn't know.
We had dozens of rear engine Amtrans with both 444 and DT engines and the cooling fans are all reverse flow meaning that the fan pushes the air out of the rear of the bus through the radiator and intercooler. Seems to work OK but if there are any oil leaks in the engine compartment this oil film is deposited on the radiator and intercooler which attracts dirt that blocks the radiator and intercooler and causes overheating. The air intake for the engine is located in the plenums on either side at the rear behind the grilles.
Cooling air goes in the sides, flows over the engine, and through the heat exchangers. The is also a bunch of sheetmetal under the bus to assist this flow strategy that gets in the way of maintenance and repairs...I was glad to see the move away from the rear mounted system.