Coolant getting into the fuel or oil.
Jet aircraft need an Auxiliary Power unit (APU) to supply power in order to get the the 2/3/4 turbines rotating before they can start them and add fuel to them. The APU needs an exhaust vent just like any other motor. The APU also supplies cabin air to the cabin while the engines are not started and the aircraft is on the ground. So the vent on the back of the aircraft is an exhaust vent for the air bleeding off of the APU.
On the very rear of the fuselage of the B747 is a round exhaust for the Auxillary Power Unit(APU). Every large passenger aircraft has an APU that is used to provide electrical & hydraulic power to the aircraft while it is on the ground (or also in the air during an emergency). The APU is a small jet engine that runs off the same fuel as the jet engines that provide thrust to the aircraft. The Wikipedia link shows a view of the APU exhaust and a view of the engine. Link: http://en.wikipedia.org/wiki/Auxiliary_power_unit http://www.honeywell.com/sites/aero/Phoenix_Repair_Overhaul3_C5D5EB8A7-6730-18D1-F595-53107B90D5DA_HAF4748F3-42EF-F1E6-0E4B-B3C77023F099.htm
Apu comes from India.
Apu was born in India
Apu
Apu Nahasapeemapetilon http://en.wikipedia.org/wiki/Apu_Nahasapeemapetilon
The World of Apu was created in 1959.
Apu - magazine - was created in 1933.
apu does in his last name: nahasapeemapetalan
James Woods
The duration of The World of Apu is 1.78 hours.
Apu Nahasapeemapetilon.