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Old 07-06-2016, 01:10 PM
martureo martureo is online now
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Join Date: May 2010
Location: DC Metro/Maryland
Posts: 15,414
Selecting an electric radiator fan

I'm well under way on my 603 powered s123 project. Finally selected a radiator and mounted it. Now I'm onto getting an electric fan.

Pertinent information:
  • This will be a pusher fan, there is less than 3 inches between the radiator and the front of the engine.
  • There will be an a/c condensor (yet to be chosen) in front of the radiator
  • I'm not going to modify the car body

I'm using the Nissens radiator for a 87 300TD. Cooling area dimensions are 24 x 18 inches --> 432 in^2

It seems that the consensus is that you want 70% of your cooling surface to be covered by a fan or shroud. This is going to be a pusher, so a shroud doesn't really help (as it would block air traveling through by motion of the vehicle).

So that's 302.4 in^2 that I need covered.

I've done a little math to try to figure out what I could get on the surface of the radiator and what would each setup cover.

2 x 10in fans
78.5 x 2 = 157 in^2

2 x 12in fans
113 x 2 = 226 in^2

1 x 16 in fans
201 in^2

I don't think I can get anything bigger than a pair of 12in fans or a single 16 in fan in front of the radiator/condenser (things start getting in the way).

Additionally I've read that a pusher fan is 15% less efficient than the same fan mounted as a puller.


So I'm left asking the question, is that enough cooling or should I be worried/looking for another option.
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I recondition w123/w126/w124/w140/r107/r129/ steering boxes!


1984 300D "Elsa" odo reset 6/2011 147k
1983 300TD "Mitzi" ~268k OM603 powered
1995 E300 "Adelheid" 262k [Sold]
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