I installed one of those 72 plate oil cooler & fan kits on my Type 3. I located
it on the horizontal surface above the transmission. The oil cooler is offset
from the surface by about 2.5 inches; the fan hangs from the cooler. The fan has
a maximum of 570 CFM.
The fan can be run as a pusher or puller by simply disassembling the fan and
reversing the fan blade assembly. My question is: should the fan pull the air
down from the cooler, or push it up through the cooler?
If the fan pushes the air from the bottom up, cold air is drawn from below but
the hot air that is expelled from the cooler ends up in the 2.5 inch space
between the cooler and the horizontal surface of the underbody. Then that hot
air travels rearward toward the engine. And in a Type 3, the engine has a lid
above it to separate the engine from the luggage compartment, so the lid is
already holding a lot of heat in against the engine. The engine lid and the
horizontal surface are on the same level.
If the fan pulls the air down from the cooler, warm air from above the cooler is
pulled through the cooler and the hot air is expelled downward. Then that hot
air travels rearward toward the engine, though in this case a bit farther away
from the horizontal surface.
Which method will give the better results? An unknown factor is how quickly the
air above the transmission gets moved along when the car is at speed.
/[cooler] | |
floorpan__________|seat/ trans engine