quote:Originally posted by David_Nunn:
Something no one has mentioned: if your radiator fan shroud does not have a baffle in the center, that isolates each fan, you need both fans to turn on at the same time. If only one fan turns on, it will draw most of its air through the large fan opening right beside it, rather than through the radiator.
When fully shrouded fans first came available a few people experienced overheating at sustained high speed due to the fact not enough air could be drawn through the fan opening. This was overcome by cutting out portions of the shroud and replacing with flaps that could self open at speed.
One aspect often overlooked for optimal fan performance is fan blade standoff from the radiator. When I installed a Flex-a-Lite system on my '74 I had to space it off the radiator to obtain the 3/4" recommended.