fan size and heat efficency

[bazz61]

hi all ,after some good advice from here and a helpful hand from a mechanic/ fellow tourist/ changed out the fan on the dx4.2 diesel ute, well had to take the radiator and shroud out as not enough clearance between radiator and fan , the replacement fan has an xtra blade and was smaller in diameter about 30 mills, anyway all good running sweet, hitched up the van to tow from Margret river to Perth then north, first hill temp gauge goes to 3/4 mark .bugger...! seems the oversize fan is the way to go , altho it has been ground down on the tips , appears to be out of a petrel model patrol according to auto 1 parts bloke , so will put in the bigger fan and will see how that goes, also a piece of old sponge fell out about 600 X 20x10 ,it was perished, anyone have any ideas on where it should go i'm thinking between bottom of shroud and radiator ,cheers Bazz,

[Bigrig]

Crikey, not sure on that one mate. Would have thought there was some sponge strip on the shroud to prevent rattle, but nothing like a sponge - wasn't there from a wash long ago was it??!! lmao

Hopefully someone can shed some light on it for you mate!!

[megatexture]

mines got foam between the bottom 2 mounts (zd30)as bit of a gap filler may help direct airflow better doubt that on its own would cause heating issue though.my hilux also has it on the sides so seems common practice if this helps

[Robo]

sponge should be from, up under rad support panel, gap fill, above air con core.
If fan doesn't fit inside shroud correctly, could be having turbulence problems.

hummmm, theory---
air flow coming off end of blades might be creating an airlock between fan and shroud, and limiting actual flow rate coming through rad core.