What do these air flaps do?, And how important are they? Options

[JeffBowlsby]

I bet most 914s don’t have these flaps anymore. These hinged flaps in the diagram are called ‘engine fan flaps’ or ‘non-return flaps’ in the parts manual. They close off the supply air duct path from the engine fan to the heat exchangers when the engine is off by gravity. They open up with the force of supply air to the heat exchangers when the engine is spinning, to circulate air through the HEs into the cabin, as assisted by the electric blower fan in the engine bay.

So the only thing I can figure is that after the car is hot and the engine is shut off, the flaps close to prevent hot air from entering the supply air fan plenum…but I can’t figure out why that’s important.

Any ideas?

[joeav8tor]

I dont think the heat has anything to do with the operation, or engineering of the flaps...when the engine is cold, the flap above the oil cooler is open, allowing the air to pass over the oil cooler, thus the warm oil is being circulated through the cooler allowing the engine to warm up more quickly...after the engine heats up, the thermostat expands, closing the flap over the oil cooler, redirecting the air to go through the cooler to aid in cooling the oil...I inspected mine when I dropped the engine for a tune up, and seals. There has been a thread on this in the past, Brad Roberts also explained it very well...either way, I think it is a good idea for the system to work, and so did the German engineers that came up with it...good luck, Happy Holidays (IMG:http://www.914world.com/bbs2/html/emoticons/flag.gif)
Joe